WORKBOOK
PHYSICS & CHEMISTRY
2º ESO
Creado por
Beatriz Jiménez Mahíllo
Esta obra está bajo una licencia
Reconocimiento-No Comercial-Compartir Igual 4.0 Internacional
CC BY-NC-SA 4.0
Este cuadernillo contiene actividades para trabajar la materia de física y química de 2º ESO en modalidad bilingüe en inglés (Comunidad de Madrid). Su fin es exclusivamente educativo, no comercial.
Todas las actividades son de creación propia, así como las imágenes. Las imágenes referentes a instrumentos de laboratorio han sido creadas con el editor Chemix (https://chemix.org/).
En el caso de que se utilice alguna reseña/cita/ilustración con derechos de autor, se hace bajo el derecho de cita e ilustración para la enseñanza. Si alguno de estos propietarios no deseara que alguno de sus materiales sea aquí empleado, debe notificarlo para su sustitución. En ningún momento se pretende vulnerar los derechos de autor, imagen o propiedad intelectual.
Unit 1. Scientific method and matter ... 1
Unit 2. States of matter ... 8
Unit 3. The diversity of matter ... 11
Unit 4. Changes in matter ... 17
Unit 5. Motion ... 22
Unit 6. Forces ... 27
Unit 7. Energy ... 29
Unit 1. Scientific method and matter
Scientific notation and operations
1. Express these numbers in scientific notation:
a) 0,00000000006 b) 570000000 c) 0,000074 d) 60000 e) 532 2. Express these numbers in scientific notation:
a) 689000000000 b) 0,0005 c) 8500 d) 0,0038 e) 0,00000000000000095 3. Change these numbers from scientific notation to standard form:
a) 4,5·10‒2 b) 9·106 c) 3·10‒4 d) 8,63·104 e) 8,42·10‒5 4. Do the following operations and express the final result in scientific notation:
5. Do the following operations and express the final result in scientific notation: Conversion factors
6. Make the following unit changes using conversion factors:
a) 600 cg to dag b) 0,02 daL to kL c) 450 hm2 to m2 d) 0,003 dm3 to mm3 7. Make the following unit changes using conversion factors and scientific notation:
a) 75000 dal to cL b) 0,06 kg to mg c) 30 mm to hm d) 450 dm2 to mm2 e) 0,0035 cm2 to dam2 f) 0,00083 dm3 to dam3 g) 500 hm3 to cm3 h) 3900 mm3 to m3 8. Make the following unit changes using conversion factors:
a) 1200 hm/min to km/s b) 50 dag/s to cg/min c) 800 cm2/g to mm2/mg d) 0,5 dg/m3 to hg/hm3 9. Make the following unit changes using conversion factors and scientific notation:
a) 760 cm/hL to dam/mL b) 7200 hm/h to dm/s
c) 3900 mg/m3 to dag/hm3 d) 5 cL/min to kL/h 10. Make the following unit changes using conversion factors and scientific notation: a) 70 cm3 to dL b) 0,003 km3 to hL
c) 850 cL to m3 d) 0,054 daL to dam3
11. Make the following unit changes using conversion factors and scientific notation: a) 600 hg/cm3 to hg/dL b) 60 cL/min to dam3/s c) 3500 dL/m2 to mm3/m2 d) 0,003 hm3/min to mL/h 12. Arrange the following amounts in order and show the process of resolution: a) 600 cm3 b) 900 cL c) 0,00004 dam3
13. a) Express the following units in the International System of units: a) 900 dm b) 120 min c) 0,00004 dam3 d) 520 mg e) 0,025 dm2 b) Identify each unit with the magnitude it is used to measure.
Scientific method
14. Each sentence below describes a step of the scientific method. Match each sentence with a step of the scientific method listed below.
1. Recognize a problem/suggest an idea you would like to study 2. State a hypothesis
3. Check the hypothesis with an experiment 4. Analyse results and draw conclusions
a) Emma said: “If I fertilize my geranium plants, they will blossom.”
b) William’s data showed that household cockroaches moved away from raw potatoes slices. c) Henry wondered if dyes could be taken out of plant leaves and flowers.
d) Andrew said: “If acid rain affects trees in a particular forest, it might affect small animals, such as ants, that live in the same place.”
e) Sophia grew bacteria from the mouth on Petri dishes (special plates) in the laboratory. She placed drops of different mouthwashes on bacteria on each plate.
f) Charlotte used a survey to determine how many of her classmates were left-handed.
g) Luke read about growing plants in water. He wanted to know how plants could grow without soil. h) Lucas saw owls catching insects at night. He asked: “How do owls find the insects in the dark?” i) Amelia soaked six different kinds of seeds in water for 24 hours. Then she planted the seeds in soil at a depth of 5 cm. She used the same amount of water, light and heat for each kind of seed.
j) Alice’s experiment proved that cockroaches move away from light.
k) Steve predicted that seeds would start to grow faster if worms moved through the soil in which they were planted.
l) Leo fed different diets to three groups of hamsters. His experiment showed that hamsters need vitamin C and protein in their diets.
m) Chloe’s experiment showed that chicken eggshells were stronger when she gave the hen feed with extra calcium.
n) Julian said: “If I grow five aloe vera plants in blue light, I think the plants will grow faster than the five plants grown in white light”.
15. Identify which step of the scientific method each statement represents and put them in chronological order.
a) I think that sliced cheese gets moldy faster because people touch it more.
b) I keep four separate sets of cheese in the refrigerator: five slices that I touch once a day; five slices that I leave untouched; five cubes of unsliced cheese that I touch once a day; and five cubes that I leave untouched.
c) After five days, both sets of cheese that I touched are moldy and the sets of cheese that I left alone have no mold.
d) Why is the sliced cheese in the fridge all moldy? We bought a block of unsliced cheese on the same day and it isn’t moldy at all.
e) I was right: touching is the critical factor in making cheese mold.
16. Mrs. Smith has a problem and she would like to solve it making use of the scientific method. Read the text, describe the steps of the scientific method she should follow and identify what she would do in each one.
Mrs Smith is training for a marathon in September. Recently in her training she has been experiencing nausea after her runs. She made some changes: eating a banana before the run, drinking Aquarius during the run and eating a piece of bread with cheese after the run. She is interested in knowing the food/drink which is causing the nausea.
17. Read the following paragraph and indentify the parts of the scientific method. What conclusion can be drawn?
A pharmaceutical company is interested in developing a new drug in order to diminish the effects of the common cold. The scientists that work for the company tested fifty volunteers, each of whom was suffering the effects of a cold. Twenty-five of the people were given the drug, while the other twenty five were given a placebo, a sugar pill. None of the participants knew who was which pill. All participants received a pill at 9:00 a.m. daily after breakfast for the first three days of the study. All participants lived in the same environment, with the same climate, eating the same diet and having the same level of activity.
The severity of the cold was determined by the number of tissues each person used within a twenty-four hour period (it would give an idea of the effectiveness of the pill). At the end of a seven-day period it was concluded that those with the sugar pill had their symptoms disappear as well as those who had taken the new drug. The executive committee decided to produce the drug anyway thinking that the public would do anything to relieve the symptoms of a cold.
18. Someone gave you a baby dragon as a present and you have to feed him because he is hungry. Follow the different stages of the scientific method and explain in order what you would do to find out what he eats.
19. Your physics and chemistry teacher wants to know if there is any relationship between eating breakfast and school performance. Identify the steps of the scientific method and explain your hypothesis, design the experiment you would put into practice and what you would study.
20. Although we do not realize it, we often use the scientific method in our daily life. In the table you have a problem and an observation you made. Develop a hypothesis to try to explain your problem and how you would test your theory with a simple experiment.
PROBLEM OBSERVATION HYPOTHESIS EXPERIMENT
a) You are talking on your mobile phone in your bedroom when suddenly the reception goes bad for a minute.
Just before the reception clears up, your brother finished a short video conference over the internet.
b) Your cat rejects a can of tuna.
She ate the can of pork you fed her last night and the beef food from the night before.
c) Your bedroom air conditioner blows very cold air at night but only cools air during the day.
Your bedroom gets lots of direct sunlight in the daytime.
21. Elizabeth wonders if dogs like all biscuits regardless of the colour. Therefore, she decides to design an experiment with her dog Lassie. In the kitchen she prepares two bowls and introduces brown biscuits and green biscuits in each one. Then she lets the dog go into the kitchen and record which bowl Lassie goes first. She repeats the procedure for thirty days. At the end of the experiment Lassie chose each bowl equally.
a) What conclusion can she get?
b) Is it important that Elisabeth uses the same type of biscuit and the same amount in each bowl? Why? 22. What experiment would you put into practice to test the following hypothesis? Hypothesis: listening to music while you are studying makes you get higher scores in your exams. Describe the experiment step by step.
23. Logan had 20 identical iron nails. She painted 10 nails and left the other unpainted. Then he put all the nails in a plastic tray and placed it outside. After 5 days, all the unpainted nails showed signs of rusting. On day 30, rust began to show through the paint on 4 of the painted nails. Five days later, all of the painted nails showed signs of rusting. Describe the steps of the scientific method and identify with what Logan did.
24. Liam and Noah wonder whether the colour of a container will affect how much heat it will retain. Liam said: “If I put hot water in a dark can and a light can, then they will cool down at the same rate”. But Noah thinks that the dark can will cool down faster. They designed and conducted an experiment using light coloured and dark coloured soup cans. They obtained the following data arranged in a table:
Time (minutes) Temperature (ºC) light can Temperature (ºC) dark can
0 (start) 100 100 5 90 70 10 70 50 15 50 30 20 40 25 25 30 23 30 25 21 35 20 20 40 20 20
a) Identify each one of the steps of the scientific method they follow. b) What conclusion do they get? Who was right?
c) Why do they arrange the data they get in a table? Is there a better way to analyse the data?
25. Two scientists want to find out which brand of shoes (Adidas or Nike) lasts longer. They think they can make an experiment based on the amount of rubber left on the bottom of each shoe after 2 years. Describe how the scientists should set up the experiment, so it is valid (take into account which variables cannot be changed).
26. For the following problems that are going to be studied, make up a possible hypothesis related to it in the form “If…., then…”. The first one is done as an example.
a) Problem: What is the relationship between frequency of brushing teeth and cavities? Hypothesis: If a person brushes his teeth more, then they will have less cavities. b) Problem: How does humidity affect the amount of time it takes clothes to dry?
c) Problem: How does the amount of water you drink affect the number of kilometres you can ride in a bicycle?
d) Problem: Is bacterial growth affected by temperature?
e) Problem: Does the amount of salt in the soil affect the growth of plants?
f) Problem: What is the relationship between the amount of car accidents and the use of a cell pone while driving?
Density
27. Complete the table and show the procedure you follow:
Mass (kg) Volume (L) Density (kg/L)
Silver 4,2 0,4
Ice 9,2 0,92
28. You go to the supermarket and buy an olive oil bottle (A) with a volume of 2 L and a mass of 1700 g. Your mother takes an olive oil bottle of another brand (B), although it has a volume of 5000 mL and a mass of 4,3 kg.
a) Which brand has a higher density?
b) What volume is needed in both cases (A and B) to take a mass of 10 kg?
29. A student performs an experiment with three unknown fluids and obtains the following measurements:
- Fluid A: m = 206 dag, V = 2000 mL - Fluid B: m = 672 g, V = 8 dL - Fluid C: m = 0,99 kg, V = 110 cL
Draw how the fluids would be layered if they were combined in a beaker.
30. You have been digging a garden and have found four different objects. You must find out the material they are made of.
Type of solid Density (g/cm3)
Marble 2,6 Muscovite 2,9 Pyrite 5,0 Copper 8,9 Gold 19,3 Platinum 21,4
While digging you find a nail with a mass of 53,4 g and a volume of 6 cm3.
You find some crystals with a mass of 15 g and a volume of 0,03 dL.
You find a ring with a mass of 107 g. You fill a graduated cylinder up with 10 mL of water and put the ring into it. Then the water rises up to the 15 mL mark.
You find a rock block. Its measurements are 3 cm by 4 cm by 6 cm. It has a mass of 1,87 hg.
31. In the laboratory scale you measure the mass of a rectangular block of lead metal, which is 1356 g. The dimensions of the block are 8 cm by 5 cm by 3 cm. From this data, what is the density of lead? Express it in the International System of units.
32. A 150 g-graduated cylinder is filled with 440 mL of carbon tetrachloride. The mass of the graduated cylinder with carbon tetrachloride inside is found to be 854 g. From this information, calculate the density of carbon tetrachloride.
33. A piece of magnesium has the shape of a cylinder with a height of 9 cm and a diameter of 4 cm. If the magnesium sample has a mass of 195 g, what is the density of the sample?
34. Obsidian is a rock with volcanic origin. A piece with a mass of 875 g occupies 350 mL. Will it float on goat’s milk?
35. In the laboratory there are four bottles that have the same mass, although different volumes. However, the labels with the values of density are wrong. Can you identify the labels with the proper bottle? Bottle 1 d=0,8 g/mL Bottle 2 d=2,1 g/mL Bottle 3 d=1,3 g/mL Bottle 4 d=0,5 g/mL
36. Knowing that the density of silver is 10,5 g/cm3, if a piece of 210 g is added to a graduated cylinder and the final level of water is 180 mL, what was the initial level?
37. a) A gold-coloured ring has a mass of 18,5 dag and a volume of 1,25 cL. Is the ring made of pure gold?
b) A mass of 386 g of gold is lowered into a graduated cylinder containing 80 mL of water. What new level will the water rise to in the cylinder?
Data: dgold=19,3 g/mL
38. Karlos Arguiñano needs 0,3 L of flour to cook a cake. Knowing that the density of flour is 620 mg/mL, how many grams of flour are needed for this recipe?
39. If 200 ml of a liquid with a mass of 280 g is mixed with 100 mL of a liquid having a mass of 80 g, what is the density of the resulting liquid?
40. How many litres of a liquid with a density of 0,9 g/cm3 are needed to balance (equal) the mass of 500 mL of aluminium?
Data: daluminium= 2,70 g/mL
41. Four liquids (A, B, C and D) with different densities are added carefully to a beaker and they are layered as it is shown in the picture.
a) Complete the chart and identify the corresponding liquid with its density.
Liquid Mass (g) Volume (cm3) Density (g/cm3)
30 50
160 100
67,5 75
630 150
b) If we add a metallic cube with a side of 3 cm and a mass of 70,2 g, where would it float?
42. Put the following substances in order of density from lowest to highest: zinc (7,1 g/cm3), honey (1400 kg/m3), baby oil (8 g/cL) and osmium (2,26 cg/mm3). Show the process (with conversion factors).
Initial
Final
A
B
C
D
43. In the laboratory Ernest measured the mass and volume of three different materials and he obtained many values that he represented in the shown graph.
a) Which material has the greatest density? Explain your answer. b) What is the density of material B?
c) Knowing that the density of water is 1 g/cm3, which material would float on water? d) Can you calculate the mass that corresponds to a 30 cm3-sample of material C?
e) For each material Ernest took 4 values of masses and volumes with different samples. Why do you think he did that?
Revision
44. Say whether the following statements are true or false. JUSTIFY your answer. a) As the density of oak wood is lower (0,7 g/cm3) than the density of ebony (2,5 g/cm3) and both balls have the same volume, the mass of the wooden ball is smaller.
b) Both cylinders have the same mass and, taking into account the volumes of each one, cork is more dense than granite.
c) Volume is an extensive property. d) Softness is a quantitative property.
e) Intensive properties are specific for each substance.
f) In the International System of units time is measured in hours.
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Material A Material B Material C wood ebony granite corkUnit 2. States of matter
States of matter
1. Complete the chart with the state of matter (solid, liquid or gas) at each temperature. Explain your answer somehow.
Substance Melting point (ºC) Boiling point (ºC) State at −70ºC State at −30ºC State at 250ºC State at 800ºC Chloroform −63 61 Carbon dioxide −78 −57 Glycerol 18 290 Nitric acid −42 83 Potassium 63 759 Titanium 1668 3287
2. Answer the questions:
a) When dry ice (the solid form of CO2, hielo seco) is heated, it sublimes at ‒78ºC. What does it mean?
b) Mercury has a melting point of ‒38ºC and it boils at 357ºC. In which state is it found at room temperature (25ºC)?
c) Ammonia is a substance with a boiling point of ‒33ºC and a melting point of ‒78ºC. What is its state at ‒33ºC? And at ‒80ºC?
d) If a substance changes from one phase to another, is it still the same substance? How can you explain it?
Heating and cooling graphs
3. Look at the following heating curve of an unknown substance.
a) Identify the state of the substance in each stage.
b) Why doesn´t temperature change during a phase change? What is happening with the provided heat? c) Look at the table. Which substance could it be?
Melting point (ºC) Boiling point (ºC)
Substance 1 ‒60 110 Substance 2 80 ‒40 Substance 3 ‒40 80 Substance 4 ‒60 80 -60 -40 -20 0 20 40 60 80 100 120 0 30 60 90 120 150 180 T ( ºC ) t (min)
A
B
C
D
E
4. Look at the following cooling graph of a substance.
a) Can we say that its particles are very close to each other at state A? b) What is the state at D?
c) How would you describe the forces among particles at state E? d) Are the particles moving faster at A than at B?
e) What is the value of the melting point?
f) In which part of the curve would the substance have a definite volume but not a definite shape? g) What is the range of temperature in which the substance remains in a liquid state?
5. Draw a temperature-time graph for the cooling process of acetone, starting at a temperature of 70ºC and finishing at ‒110ºC. Take into account that acetone’s fusion and boiling points are ‒95ºC and 56ºC, respectively.
6. The graph shows two substances in a liquid state that are cooled down.
a) Which substance cools down more slowly?
b) What is the temperature at which the change of state takes place for each substance? How do you call that temperature in this specific case?
c) Draw a sketch for the particles of B at the third stage. d) Are substances A and B the same? How do you know?
e) Are the bonds among particles becoming stronger or weaker in this change of state?
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Kinetic molecular theory
7. In the laboratory you heat a conical flask with oil and when you pay attention to the level of the liquid you notice that it is higher when it is hot. Explain what happened according to the kinetic theory.
8. Explain the following phenomena using the kinetic molecular theory:
a) When a basketball (full of air) is left outside in a sunny day, the volume of the ball is bigger after a while.
b) When you push the plunger of a syringe that only contains air while keeping it closed with your finger, you can compress it a little bit.
c) When you light a candle, the wax melts and it flows down.
d) When we leave a bottle of perfume open in a room, the scent spreads all over the place.
e) When you have a steamy shower, the mirror in the bathroom fogs up and small droplets of water appear on its surface.
f) When you breathe outside in the winter and it is very cold a cloud comes out of your mouth.
Revision
9. Use the terms in the vocabulary box to fill in the blanks. Use each term only once. You do not need to use all the terms.
slide less expands faster
more easily contracts volume
vibrate high boiling lower
evaporation kinetic molecular theory freely raise
mass slower matter sublimation
rigid flow condensation melting
a) The __________________________explains how particles act according to its state. b) Gas particles move ____ _ at _____ speed.
c) Particles in a solid are tightly packed so they can only ____________. d) In a liquid particles flow_____ and ___ past each other.
e) Sometimes a liquid can become a gas without any extra energy and this process is called _____________.
f) Atoms in a liquid have ______ energy than atoms in a solid. g) ____________ is the amount of space that a material takes up. h) ____________ is the amount of material that makes up something.
i) When you remove energy from particles they move_______ and the matter______________.
j) To change a gas to a liquid you will need to _______the temperature. The ____________point is the temperature at which the gas becomes a liquid.
10. State whether the following statements are true or false. JUSTIFY IN DETAIL your answer in every case.
a) Chlorine, with a melting point of −34ºC and a boiling point of −101 ºC, is in a liquid state at −50ºC. b) When we heat a substance and it boils the energy is being used to move its particles faster.
c) Condensation is a regressive change.
d) Evaporation takes place only at the boiling point. e) Subliming ice is the opposite process of freezing water. f) When energy is added to matter particles take up less space. g) In a liquid the strength among particles is bigger than in a solid.
Unit 3. The diversity of matter
Classification of matter
1. Classify each of the materials in the table. First you must state whether the material is a pure substance or a mixture and then, if the material is a pure substance, classify it as either an element or compound in the right column. In a similar way if the material is a mixture, classify it as homogeneous or heterogeneous in the right column.
Pure substance: element/compound, Mixture: homogeneous/heterogeneous Pure substance
or mixture Material
1) concrete (water, rocks and cement) 2) sugar + pure water (C12H22O11+H2O)
3) aluminium filings (Al) 4) limestone (CaCO3)
5) orange juice (with pulp) 6) Cantabric Sea
7) air inside a balloon 8) iron (Fe)
9) graphite (C) 10) acetone (C3H6O)
11) tap water in a glass 12) soil
13) hydrogen peroxide (H2O2)
14) manganese (Mn)
15) salt + pure water (NaCl + H2O)
16) benzene (C6H6)
17) muddy water
18) bronze (Cu mixed with Sn) 19) baking soda (NaHCO3)
20) oxygen (O2)
2. Classify each of the pictures by placing the correct label in the blanks below. E = Element
C = Compound
ME = Mixture of elements MC = Mixture of compounds
Each circle represents an atom and each different colour represents a different kind of atom. If two atoms are touching then they are bonded together.
1. 2. 3.
4. 5. 6.
7. 8. 9.
10. 11. 12.
13. 14. 15.
3. Complete the table. For each sentence you can only tick one option (element, compound or mixture).
Element Compound Mixture
1. Can be separated physically 2. Made up of one type of atom only 3. Made up of two or more atoms chemically joined
4. Made up of two or more atoms mixed but not chemically joined
5 All found in the periodic table
6. Always contains atoms in the same proportion
7. Properties are the same as the atoms that make it up
4. In the laboratory you try to obtain the melting point of butter, so you heat a sample and record time and temperature for a while. You observe that it starts to melt at 30ºC and it is fully melted at 45ºC, as it is represented in the graph you did. Why don’t you get a specific value of the melting point?
Separation of mixtures
5. A student used paper chromatography to separate the ink of the dyes present in a marker. He placed spots of four known dyes (A. B, C and D) and one spot with the ink in the marker (X) he wants to analyse. The picture shows the appearance of the paper before and after the experiment.
a) Explain how paper chromatography separates substances. b) Explain why dye D did not move during the experiment.
c) What do the results tell you about the composition of the ink in the marker?
6. Some farm-raised salmon are provided colour through their diets by ingesting coloured additives in the food they are given in order to enhance the colour of the meat. Only some additives are allowed. Explain how you could use the technique of chromatography to check if the farmers are using the proper additive if you took a sample of the salmon skin.
7. Do a diagram (flow chart) to show the process of separation of a mixture of rice, iron nails, sand and oil.
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8. Do a flow chart to show the process of separation of a mixture of salt, iodine, aluminium fillings and pebbles.
Hint: iodine sublimes
9. Do a diagram (flow chart) to explain how you would separate a mixture of sugar and salt. Hint: sugar cannot be dissolved in alcohol, but salt can
10. Indicate the laboratory equipment you would need to separate a mixture of flour, potassium chloride, pentane and water and explain how you would use it in order.
Hint: pentane is a liquid that is immiscible with water; potassium chloride is a salt that can be dissolved in water, but not in pentane
11. The diagram shows the set-up for the process of distillation. a) Label the different instruments.
b) Name the changes of state that take place in A and B.
c) Indicate the proper direction of the flow of water in 1 and 2. Explain your answer.
d) In the boiling flask there is a mixture of heptane and octane. What compound will be collected in the conical flask?
Data: Tboiling (heptane) = 98ºC; Tboiling (octane)=125ºC
Solutions, concentration and solubility
12. For each of these solutions identify the solute and the solvent and the respective state. The first one is done as an example.
Solution Solute Solvent
champagne bubbles of CO2 (gas) water (liquid)
moist air bronze whisky syrup
13. The glass contains a solution. Label the different components and explain it.
14. In order to make 400 mL of solution, 25 g of glucose (C6H12O6) are dissolved in enough water.
Calculate the concentration of the solution in g/L.
15. What is the concentration (in g/L) of a solution prepared by dissolving 2,2 hg of sucrose (C12H22O11)
in 50 cL of solution?
16. How many grams of hydrochloric acid (HCl) are present in 600 mL of a solution with a concentration of 25 mg/L?
17. You want to prepare a potassium chloride (KCl) solution with a concentration of 0,6 g/cL. If you take 15 dag of potassium chloride, how many litres of solution will you need?
18. In the laboratory there is a flask with a solution of sulphuric acid (H2SO4) with a concentration of
350 g/L. How much sulphuric acid there will be if the flask contains 100 mL of solution?
19. How many millilitres of solution are required to dissolve 3000 cg of acetone (C3H6O) in water in
order to obtain a solution with a concentration of 25,5 g/dL?
20. When you went to the beach last summer you took a 300 mL-sample of seawater from the Cantabric Sea. In the laboratory you heat it until it is evaporated and it leaves a residue of 12 g of salt. What concentration of salt (in g/L) does the Cantabric Sea have?
21. Indicate what instruments you would use in the laboratory to prepare a solution of certain salt in water. Describe the process you would use.
22. Explain if the following sentences about a solution of copper sulphate (CuSO4) in water with a
concentration of 30 g/L are true or false:
a) There are 30 g of copper sulphate in 1 L of water. b) There are 15 g of copper sulphate in 500 mL of solution. c) There are 30 g of solvent in 1 L of solution.
d) If you add more solvent to the solution it can become saturated.
23. In the laboratory you consult the solubility for sugar in water in a handbook and it is 200 g/100 mL of water at 20ºC. How much sugar can you dissolve at the same temperature in 400 mL of water?
24. The graph represents the solubility curve for two different substances. Answer the questions: a) What is the value of solubility for substance 1 at 40ºC? Explain in your own words what it means. b) How many grams of substance 2 you must add to 100 g of water at 10ºC to form a saturated solution? c) What kind of solution (saturated, supersaturated or unsaturated) would you have at 80ºC if you added 40 g of substance 2 to 100 g of water?
d) Imagine you dissolve 70 g of substance 1 in 100 g of water? At what temperature would you obtain a saturated solution?
25. The graph shows the solubility curves for three different substances (grams of solute that can be dissolved per every 100 g of water) at different temperatures.
a) Which substance’s solubility is most affected by increasing the temperature of the water? Use evidence from the graph to explain your answer.
b) Imagine you have to dissolve certain amount of C in water. Is it a good idea to heat the solution in order to achieve it?
c) At what temperature (approximately) would you say the solubility of A and C are the same? d) Which substance is the most soluble in water at 80ºC?
e) Which substance is the least soluble in water at 40ºC?
f) What kind of solution would you have if you dissolved 60 g of substance A in 100 g of water at 60ºC? And at 80ºC?
Revision
26. State whether the following statements are true or false. JUSTIFY your answer. a) A chocolate chip cookie can be considered as a heterogeneous mixture.
b) When you apply the process of distillation for a mixture with two miscible liquids A and B, you will have to condensate the liquid with the higher boiling point.
c) A solution can be dilute and saturated at the same time. d) In a solution the solvent is always water.
e) When the volume of solvent increases the amount of solute that can be dissolved in a saturated solution could increase.
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Unit 4. Changes in matter
Periodic table
1. Answer the questions related to the given periodic table. You do not need to consult the real periodic table.
a) In which period and group is element A? b) What is the atomic number of B?
c) How many electrons does element C have if it is neutral? d) Are elements D and E in the same period?
e) Can you know the number of neutrons of element E just looking at the table? And the number of protons?
2. Complete the table as shown in the example. You will need the periodic table.
Name (English) Nombre (español) Symbol Group Period
Cesium Tin 11 5 Azufre Au Molybdenum 14 6
Atoms and ions
3. Answer the following questions:
a) What information would you need to find the chemical element of an atom? b) What does the atomic number represent?
c) What does the atomic mass represent?
d) Where is the majority of the mass located in the atom? e) Is an atom electrically neutral? Why?
f) How are the elements organized in the periodic table?
4. Represent the atom according to Thomson, Böhr and Rutherford’s ideas.
A
B
E
5. Identify this atom (consult the periodic table) and write it with the notation .
6. Fill in the blanks:
Symbol Element Cation or anion?
Z A Nº protons Nº neutrons Nº electrons
Cu 64 29 Cd 112 48 Ba 56 81 Sr2+ 88 50 Br− 45 36 Hg+ 80 201 Sb3− 51 71
7. Complete the table:
Charge Nº protons Nº electrons Nº neutrons A Z
+2 28 24
‒ 53 127
79 79 197
+4 74 117
‒2 54 128
8. With the given information, write the notation of the atoms in the form of (don’t write the symbol of the element, leave it as X).
a) It has 22 protons, 26 neutrons and 20 electrons.
b) It has 51 protons and 72 neutrons and it has gained 2 electrons. c) Its mass number is 207 and it has 82 protons.
d) It has 31 protons and 29 neutrons and it has lost 3 electrons.
9. With the following information, write the atom with the notation . Once you know the atomic number, go to the periodic table to find the symbol.
a) It contains 37 protons, 48 neutrons and it has lost 1 electron. b) It is a neutral atom with 53 electrons and 74 neutrons.
c) It is an anion that has 36 electrons (including the 2 electrons it gained) and 45 neutrons. d) It is a cation with a mass number of 55 and 22 electrons (it has lost 3 electrons).
protons
neutrons
10. Determine the final electric charge and the sign (positive or negative) for the atoms that undergo the following process:
a) A neutral atom loses 3 electrons. b) An ion of charge +2 gains 3 electrons. c) An ion of charge ‒3 loses 1 electron. d) An ion of charge ‒1 gains 4 electrons. e) An ion of charge +1 loses 3 electrons.
11. Complete the table. You will need to consult the periodic table to know the symbol. The first one is done as an example.
Nº of protons Nº of electrons Ion
11 10 Na+ 22 18 83 86 49 46 16 18 53 54 37 36
Structure of elements and compounds
12. Identify each drawing with the proper description: molecular compound, simple molecular substance, simple crystalline substance, crystalline compound, simple elemental substance.
a b c d e
13. Using two kinds of balls, do a diagram to represent: a) A molecular compound.
b) A mixture of simple compounds. c) A simple substance.
d) A crystal made of one type of element.
14. In the diagrams the black balls represent atoms of chlorine and the white balls are atoms of nitrogen. Explain what substances they represent in each case and write its formula.
Chemical reactions
15. Classify these examples as chemical or physical changes: 1. Aluminum foil is cut in half.
2. Milk goes sour. 3. Bread becomes toast.
4. Rust forms on a nail left outside. 5. A juice box in the freezer freezes. 6. A match is lit.
7. Rubbing alcohol evaporates on your hand. 8. You fry an egg.
9. Your body digests food.
10. Hydrogen peroxide bubbles in a cut. 11. Clay is molded into a new shape. 12. Whipping egg whites.
13. Dissolving sugar in water. 14. Gasoline burning.
16. Balance the following chemical reactions: a) NO + O2 → NO2
b) SO2 + O2 → SO3
c) Na2O + H2O → NaOH
d) HNO3 + NaOH → NaNO3 + H2O
e) Zn + HCl → ZnCl2 + H2
f) Al + HCl → AlCl3 + H2
g) Na2SO4 + C → Na2S + CO
h) HCl + O2 → H2O + Cl2
i) Fe + O2 → Fe2O3
17. Balance the following chemical reactions: a) N2 + H2 → NH3
b) CH4 + F2 → CF4 + H2
c) NH3 + O2 → NO + H2O
d) CaO + MnI4 → MnO2 + CaI2
e) SiO2 + HF → SiF4 + H2O
f) Al + NaOH → Na3AlO3 + H2
g) H3PO4 + HCl → PCl5 + H2O
h) V2O5 + HCl → VOCl3 + H2O
i) HClO4 + P4O10 → H3PO4 + Cl2O7
18. Using the diagram below and the given information, write the chemical reaction that takes place, balance it and explain the process with the collision theory.
+
+
atom A atom B
19. In the following chemical reaction: CH4 + O2 → CO2 + H2O
a) Identify the reactants and the products. b) Balance it.
c) Represent it with a diagram of balls. d) Indicate the broken and the formed bonds.
Revision
20. Say whether the following statements are true or false. JUSTIFY your answer. a) If an atom gains protons, it changes into a cation of the same element.
b) An atom with a negative charge of 3− that has 83 protons in the nucleus will have 80 electrons. c) The notation for an atom with 28 protons, 31 neutrons and 26 electrons is .
d) The ion
has 152 subatomic particles. e) The nucleus of an atom has a positive charge.
f) The mass number of an atom with 20 protons, 21 neutrons and 18 electrons is 38.
g) Atoms of the same chemical element can have a different number of protons in the nucleus.
h) Protons and electrons make up most of the mass of an atom. i) The represented atom corresponds to oxygen (O).
Unit 5. Motion
Uniform motion
1. Change the following speeds to the International System of units using conversion factors: - The Bugatti Chiron is a very fast car. It can reach a speed of 500 km/h.
- A plague of locusts flies approximately at 150 km/day.
- In a greyhound race this type of dog can get a speed of 69,6 dm/min.
2. Arrange the following speeds in increasing order and show the process (with conversion factors): - The golden eagle can fly at a speed of 250 mph (mile/h).
- A cheetah runs at 30,5 m/s.
- The green iguana moves at 60 dam/min. Data: 1 mile is equivalent to 1,6 km.
3. A train travels 86,4 km in 90 minutes. Calculate its speed in the International System of units. 4. A van travels at 25 m/s for 2 minutes. How far has it travelled in this time?
5. A skier travels at 30 km/h. How far (in metres) will he be in 90 s?
6. Elizabeth drove to a friend’s house at a speed of 54 km/h. She came back home by the same route at a rate of 45 km/h and it took her 36 min. How much time did she need to go to her friend’s house?
7. A biker covers 108 km at a speed of 18 km/h. How much time does he need to cover that distance? 8. A car travels at constant speed and covers 16 m in 2 s.
a) How long would it take the car to travel 2 km?
b) What distance would it cover in 3 min at the same speed?
9. Flash and Superman are in a race. Who will win if Flash runs 156 m in 13 s and Superman flies 44 m in 4 s?
10. A family travels in a car between a city and a town that are separated 108 km and it takes them 90 min to finish the journey.
a) Calculate the speed of the car in the International System of units.
b) If a lorry leaves the city 18 minutes later than the car and it needs to arrive at the town before the car, what minimum speed should it have?
11. A man riding a bicycle moves in a roundabout with a radius of 3 m from point A to point B. Calculate the displacement and the covered distance in the following cases:
a) When he follows path 1 (he moves around the roundabout). b) When he follows path 2 (he moves in a straight line).
c) When, after going from A to B, he goes back to A through path 2.
City
Town
108 km
A
B
3 m
path 1
path 2
12. A man swims clockwise around a swimming pool and wants to know how far he has travelled at certain points.
a) Calculate the distance travelled and the displacement between the following points. Draw the displacement (remember that displacement is a vector and direction is important).
a1) A and H a2) D and G a3) B and F a4) G and C a5) E and A
b) If he swims around the pool 4,5 times, what is the distance that he has travelled? What is his displacement?
c) What is the distance and the displacement when he completes 3 laps?
13. A ladybird moves in a straight line looking for insects. Initially it is at a position of ‒20 m and goes forward to position A in 15 minutes. Then it turn backs and goes to B in 10 minutes.
a) Calculate its displacement and explain what it means.
b) Calculate its average speed for each stage and for the whole movement.
c) Draw the position-time graph that corresponds to the motion taking into account that it has a uniform motion in each stage.
14. Look at the position-time graph that corresponds to a rectilinear motion. a) Describe the movement in each section.
b) Calculate the average speed for the whole movement and in each section. c) Calculate the total distance the moving object covers and its displacement.
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15. A horse and a dog move in a rectilinear motion as shown in the graph. a) Calculate the average speed of each animal for the whole movement. b) Determine the displacement of each one.
c) Do they meet at any moment?
d) How far apart are from each other when the time starts?
16. According to the graph about the position of two cars:
a) Which car moves faster during the first stage? Is it necessary to calculate the speed to know it? Why? b) What distance does it car travel?
c) How far away are they are the end? d) Calculate the displacement of each one.
17. Look at the position-time graph that corresponds to several moving objects (A, B, C, D and E) in a rectilinear motion.
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a) Which ones are moving backwards? How do you know? b) Which one is the fastest one?
c) Do D and E have the same speed?
d) Which ones are moving at the same speed?
18. Jack is running a race in a straight line and he initially moves 60 m in 30 s with constant speed. Then he stops for 10 s and runs at 2 m/s during 20 s. He realizes he has forgot his backpack and goes backwards where he had stopped in 60 s. Represent his motion in a position-time graph.
19. Diana went for a walk. She started at 8 a.m and walked 8 km in the first 2 h. After resting for 30 min she walked a further 5 km in the next hour. She spent half an hour (30 min) having lunch before beginning the return trip, which she walked without stopping for 3 h. She did all the movements with a constant rate.
a) Draw the position-time graph that represents Diana’s hike. b) Calculate its average speed.
20. Look at the velocity-time graph that corresponds to a rectilinear motion. a) Explain the kind of motion in each stage and the information you can gather. b) Calculate the total space the moving object covers.
Uniformly accelerated motion
21. A motorbike that is moving at a speed of 72 km/h needs to overtake a car in a road, so it needs to get a speed of 90 km/h in a time of 4 s to do it a safe way. If the motorbike has a maximum acceleration of 0,5 m/s2, can it do it? How much time will it need?
22. A motorbike going at 90 km/h brakes at −5 m/s2. Calculate its speed after 2 s.
23. How much times does it take an airplane to stop completely if, travelling at a speed of 40 m/s it brakes at −2 m/s2
?
24. What is the initial speed of a rocket that needs 10 s to accelerate and reach a speed of 60 m/s at a rate of 4 m/s2?
25. A car moves at 16 m/s for 2 minutes. Then it brakes until the speed is 6 m/s in 1 minute and then it continues at that speed for 3 minutes. Draw a speed-time graph for the car.
26. A car, originally at a speed of 2 m/s, accelerates until its speed is 22 m/s in a time of 10 s. Then it maintains its speed for 5 s and brakes at −3 m/s2
until it gets a speed of 4 m/s. Draw the speed-time graph for this car.
27. Look at the speed-time graph that corresponds to a rectilinear motion. a) Identify the kind of movement in each section.
b) Calculate the acceleration in each section.
c) Draw the acceleration-time graph that describes the motion.
28. This acceleration-time graph corresponds to the movement of an airplane that moves in a straight line.
a) If the initial speed of the airplane is 40 m/s, what is its final speed at the end of stage A?
b) What is the distance it travels during stage B?
Revision
29. Say whether the following statements are true or false. JUSTIFY your answer. a) The graph corresponds to a car with uniformly accelerated motion.
b) Acceleration cannot be negative.
c) A bullet is shot from a rifle with a speed of 72 m/s and it reaches a target 324 m away. Therefore, it needs 0,25 s to get there.
d) Peter woke up late and he had to be at his office, which is 3,6 km away, by 7:55. He left his house at 7:15 and travelled at a constant speed of 2 m/s. We can be sure that he arrived late.
e) A man moves from A to B through the dotted trajectory. We can be sure that his displacement is shorter than the distance he covers.
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Unit 6. Forces
Mass and weight
1. The mass of a motorcycle is 250 kg. a) Calculate its weight on the Earth. b) Calculate its weight on the Moon. c) Calculate its mass on the Moon. Data: gEarth= 9,8 m/s2; gMoon=1,6 m/s2
2. Martha, with a mass of 60 kg travels to two different planets (Byss and Orthe). Complete the chart and show the procedure:
Planet gravity (m/s2) Mass of Martha (kg) Weight of Martha (N)
Byss 4,5
Orthe 780
3. Of all the planets in our solar system, Jupiter has the greatest value of gravitational acceleration. If a 400 g book weighs 10 N on Jupiter, what is the value of gravity there?
4. The weight of a pony standing on Earth is 1029 N. Draw the pony and represent the weight as a force. a) What is the pony’s mass?
b) Where will the pony weigh less, on Mars or on Neptune? Look at the data and explain your answer without doing the calculations.
c) Where will the pony have less mass, on Mars or on Neptune? Data: gEarth= 9,8 m/s2; gNeptune= 11,3 m/s2; gMars=3,6 m/s2
5. In a strange planet you use a dynamometer you measure the weight of a 7,5 kg pumpkin. If the scale reads 19,5 N, what is the value of gravity at that location?
6. A bag weighs 90 N on planet A, where the value of gravity is 15 m/s2. What is the weight of the bag on planet B, where gravity is 20 m/s2?
7. Peter has a mass of 60 kg on the Earth. He travels to Saturn because he wants to lose weight. Did he follow the correct procedure?
Data: gEarth < gSaturn
8. In the physics sense, when people go on a diet, do they really want to lose weight or mass?
Hooke’s law
9. What information does the elastic constant of a spring give? For example, what does it mean that the elastic constant is 5 N/m?
10. Calculate the force you need to apply to a spring with an elastic constant of 200 N/m to stretch it 1 dm. Draw the involved forces in this process.
11. Determine the constant of elasticity k of a spring (in the International System of units) that compresses 2 cm when a 50 N force is applied.
12. A 45 cm spring has an elastic constant of 150 N/m. Calculate: a) The force applied to get a length of 75 cm.
13. A 25 cm-long spring stretches to 30 cm when we pull it with a force of 2,5 N. Calculate: a) Its elasticity constant in the International System of units.
b) The extension of the spring (in m) when we pull it with a force of 5 N and its final length.
14. The following graph was made from data collected from two different springs when different forces were applied.
a) Determine the elastic constant for each spring.
b) Which spring is easier to compress? How do you know? c) What force would you need to apply to stretch a spring 6 m? 15. A dynamometer has an elastic constant of 90 N/m.
a) What force have we applied if it has stretched by 8 cm?
b) If we pull it with a force of 54 N, how many centimetres will it stretch?
16. A spring with an elastic constant of 6 N/cm is stretched with a force of 24 N until its final length is 78 cm. Calculate its initial length.
Weight and Hooke’s law
17. We have a 3 kg mass. a) How much does it weight?
b) If we hang the mass from a spring and measure an elongation of 5 cm, what is the spring constant? Data: g= 9,8 m/s2
18. We hang a 5 kg mass from a spring with an elastic constant of 750 N/m. How much does it stretch (in cm)?
Data: g= 9,8 m/s2
Revision
19. Say whether the following statements are true or false. JUSTIFY your answer. a) A 20 g object has a weight of 100 N on a planet with a gravity of 5 m/s2.
b) An alien that travels from planet A to planet B, where gravity is the double, will double its mass too. c) A force of 160 N is applied to a spring with an elastic constant of 8 N/cm,
so it stretches 20 m.
d) When we stretch a spring as shown in the figure (it moves to the right), the spring force is applied to the right too.
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Unit 7. Energy
Kinetic, potential and mechanical energy
1. Make the following unit changes using conversion factors:
a) 209 cal to J b) 625 J to cal c) 50 kJ to cal d) 8,36 kcal to J Data: 1 cal= 4,18 J
2. Calculate the kinetic energy of a 45 g ball travelling at 216 km/h.
3. How fast (in km/h) must a 1000 kg car be moving to have a kinetic energy of 200 kJ?
4. Calculate the mass of a canoe moving down the river with a kinetic energy of 5 J and a speed of 0,5 m/s.
5. A mosquito has a mass of 5 g. Given that its kinetic energy is 40 mJ and knowing that it is moving with uniform motion, how far will it travel in one hour? Caareful with the units.
6. A 800 g dog is running and it has a kinetic energy of 10 J. Calculate its speed.
7. A coconut falls out of a tree 12 m above the ground and hits a bystander 1,8 m tall on the top of the head. It bounces back up 1,2 m before falling to the ground. If the mass of the coconut is 2 kg, calculate the potential energy of the coconut relative to the ground at each of the following sites:
a) While it is still in the tree.
b) When it hits the bystander on the head. c) When it bounces up to certain height. d) When it lands on the ground.
Data: g= 9,8 m/s2
8. How high would you have to lift a 5 ton lorry to give it a potential energy of 300 kJ? Data: g= 9,8 m/s2
9. What is the mass of a statue sitting on a stand at 3 m of height if its potential energy is 1470 J? Data: g= 9,8 m/s2
10. A man shoots a 20 g-arrow so it moves at a speed of 18 km/h at a height of 2 m above the ground. Calculate its mechanical energy.
Data: g= 9,8 m/s2
11. A 300 g-bird flies at a speed of 12 m/s. Knowing that its mechanical energy is 139,2 J, at what height is it flying?
Data: g= 9,8 m/s2
12. A cannon shoots a 40 kg ball at a sailing ship, so it gets a height of 10 m and its mechanical energy is 4240 J. Calculate the speed it has.
Data: g= 9,8 m/s2
Transformation of energy
13. This graph shows a ball that starts at point A and rolls. a) At what letter does the ball have the greatest kinetic energy?
b) Which letter shows the ball when it has the maximum potential energy? c) Which letter shows the ball when it has the least potential energy? d) Will the ball reach point G (at the same height at which it started)?
14. Energy transformation is the process of changing energy from one form to another. Complete the table. The first example is done.
Example Energy in Energy out
1 torch (linterna) chemical energy in the battery radiant energy (light)
2 radio radiant energy (sound)
3 kettle
4 a cow moving 5 burning a candle
6 potential energy kinetic energy
7 iron (plancha) thermal energy
15. A car is moving at certain speed but, suddenly, the driver has to step on the brakes. What happened with the kinetic energy the car initially had?
Revision
16. Say whether the following statements are true or false. JUSTIFY your answer. a) A toaster changes thermal energy into chemical energy.
b) A bowling ball rolling down the alley contains kinetic energy. c) The lower the mass of an object, the higher the potential energy is.
d) Two identical books are placed on two different shelves. The book on the lowest shelf has a lower potential energy than the other book.
Unit 8. Temperature and heat
Temperature and mechanisms of heat transfer
1. Complete the chart and show your calculations:
Temperature (ºC) Temperature (K) Temperature (ºF) 500
878
1040 ‒150
2. In the following examples identify the way heat is being propagated (conduction, convection or radiation) that takes place.
a) Eggs cooking in a frying pan. b) Snowman melting in the sun. c) Water boiling in a kettle. d) Roasting sausages over a fire. e) Heating a pot on a stove.
f) Warming a room with a fireplace.
3. When you fill a ceramic mug with hot coffee the mug warms up quickly. How does heat conduction occur in the ceramic itself?
4. Is it a good idea to install an air conditioning machine at the bottom of a room? Why?
5. An engineer designs a metallic bridge and he leaves some expansion joints, useful for the summer. Explain why he decided to do this.
6. Many winter coats are made up of wool. Do you think that wool is a good thermal conductor of heat? 7. The drawing shows to systems at different temperatures (T1>T2) that have
been put together. Can you explain how the heat transfer will take place until it reaches a state of thermal equilibrium?
8. Liquid thermometers are based on thermal expansion. Can you explain how they work?
Revision
9. Say whether the following statements are true or false. JUSTIFY your answer. a) Radiation is a way of transfer of heat by contact.
b) Convection consists of the heat transfer in fluids without motion of molecules. c) In the process of conduction it is necessary to have direct contact.
d) When a liquid is heated it contracts.
