States of matter Banker

1. (a) Describe the arrangement and the motion of the particles in a solid. [2]
2. (b) Describe the arrangement and the motion of the particles in a gas. [2]
3. (c) Use your answers to explain why a gas can be compressed but a solid cannot. [1]

1. (a) Name the change of state in each of these everyday events.(i) Ghee in a pan turns to liquid when heated.(ii) Drops of water form on the outside of a glass of cold lassi on a humid day.(iii) A puddle on a road in Multan disappears on a sunny afternoon without boiling.(iv) Molten candle wax turns solid as it cools. [4]
2. (b) State which two of the changes in (a) are exothermic. [2]

The table shows the melting points and boiling points of four substances, P, Q, R and S.Substance | melting point / °C | boiling point / °CP | −218 | −183Q | −7 | 59R | 801 | 1413S | 17 | 118

1. (a) State the physical state of each substance at 25 °C. [2]
2. (b) Which substance is a solid at 10 °C but a liquid at 25 °C? [1]
3. (c) Which substance has the strongest forces of attraction between its particles? Give a reason. [2]

1. (a) Which statement describes the particles in a liquid?A regular arrangement, vibrating about fixed positionsB close together, random arrangement, moving past one anotherC far apart, random arrangement, moving quickly in all directionsD far apart, regular arrangement, not moving [1]

1. (a) A substance melts at −39 °C and boils at 357 °C. What is its state at −50 °C and at 25 °C?A solid at −50 °C, liquid at 25 °CB liquid at −50 °C, liquid at 25 °CC solid at −50 °C, gas at 25 °CD liquid at −50 °C, gas at 25 °C [1]

1. (a) A student leaves wet school uniform on a washing line on a hot, windy day in Hyderabad. Describe, in terms of particles, how the water evaporates. [2]
2. (b) Suggest why the uniform dries faster on a hot day than on a cold day. [1]
3. (c) State one difference between evaporation and boiling. [1]

1. (a) A cook seals a bag of crisps at sea level in Karachi and takes it on a trip to Skardu, where the air pressure outside the bag is much lower. The bag swells. Use ideas about gas particles to explain why the bag swells. [2]
2. (b) Gases fill any container they are put in. Explain why. [1]

A student heats a sample of solid X in a boiling tube in a water bath and records its temperature every minute.Time / min | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8Temperature / °C | 52 | 64 | 74 | 80 | 80 | 80 | 80 | 87 | 93

1. (a) State the melting point of X. [1]
2. (b) State the physical state(s) of X between 3 minutes and 6 minutes. [1]
3. (c) The water bath is still heating the tube between 3 and 6 minutes. Explain why the temperature does not rise. [2]
4. (d) Suggest why the water bath is used instead of heating the tube directly in a Bunsen flame. [1]

Liquid Y is allowed to cool in a boiling tube. Its temperature is read every 30 seconds.Time / s | 0 | 30 | 60 | 90 | 120 | 150 | 180 | 210 | 240Temperature / °C | 85 | 77 | 70 | 69 | 69 | 69 | 69 | 63 | 58

1. (a) Use the results to find the freezing point of Y. [1]
2. (b) Explain, in terms of particles and energy, why the temperature stays constant between 90 s and 180 s even though the tube is losing heat to the room. [2]
3. (c) Describe how the movement of the particles of Y changes as it goes from 85 °C to 58 °C. [2]

1. (a) A bicycle tyre is pumped up in the morning. By mid-afternoon in a Lahore summer, the pressure in the tyre has increased, although no air has been added. Explain this in terms of the air particles. [3]
2. (b) Suggest why drivers are advised to check tyre pressure when the tyres are cold. [1]

1. (a) A gas syringe contains 80 cm³ of air. The end is sealed and the plunger is pushed in until the volume is 40 cm³. The temperature does not change. State what happens to the pressure of the air. [1]
2. (b) Explain your answer in terms of particles. [2]
3. (c) Explain why it is much harder to compress water in the same way. [1]

1. (a) Which change of state involves the particles gaining energy and moving from touching each other to being far apart?A condensingB freezingC meltingD boiling [1]

1. (a) Ethanol boils at 78 °C and water boils at 100 °C. Equal volumes of each are placed in two identical dishes in the same room. Predict which liquid will evaporate faster. [1]
2. (b) Explain your prediction in terms of the forces between particles. [2]
3. (c) A few drops of ethanol on the back of your hand make it feel cold. Suggest why. [1]

1. (a) A balloon filled with air at 30 °C is placed in a freezer at −18 °C. The pressure on the outside of the balloon stays the same. Describe what happens to the volume of the balloon. [1]
2. (b) Explain your answer in terms of the motion of the particles. [2]

1. (a) Explain why a solid has a fixed shape but a liquid takes the shape of its container. [2]
2. (b) Both solids and liquids have a fixed volume. Explain why. [1]

A student traps air in a gas syringe and puts it in a water bath. The pressure is kept constant. The volume is read at four temperatures.Temperature / °C | 20 | 40 | 60 | 80Volume / cm³ | 48.0 | 51.2 | 54.4 | 57.6

1. (a) Describe the relationship between temperature and volume shown by the results. [1]
2. (b) Calculate the increase in volume for each 1 °C rise in temperature. [1]
3. (c) Predict the volume of the air at 70 °C. [1]
4. (d) Explain, using the kinetic particle theory, why the volume increases. [2]

A refill can for a camping stove contains liquid butane, C₄H₁₀, under pressure. When the valve is opened, the butane boils and comes out as a gas.[Ar: C, 12; H, 1. One mole of any gas occupies 24 dm³ at room temperature and pressure.]

1. (a) 2.9 g of liquid butane escapes. Calculate the volume of this butane as a gas at room temperature and pressure. Give your answer in cm³. [2]
2. (b) The density of liquid butane is 0.58 g/cm³. Calculate the volume of the 2.9 g of liquid butane. [1]
3. (c) Calculate how many times larger the volume of the gas is than the volume of the liquid. [1]
4. (d) Use the kinetic particle theory to explain the large difference in volume. [1]

Nitrogen melts at −210 °C and boils at −196 °C. A technician pours some liquid nitrogen from a flask onto a laboratory bench at 22 °C.

1. (a) State the physical state of nitrogen at −200 °C and at −190 °C. [1]
2. (b) The liquid nitrogen boils violently on the bench. Explain why, in terms of energy transfer and particles. [2]
3. (c) A white mist forms in the air just above the boiling nitrogen. Suggest what the mist is and explain how it forms. [2]

1. (a) Water is boiled in a kettle. The heater supplies energy at a steady rate, but the temperature of the water stays at 100 °C while it boils. Explain why. [2]
2. (b) A scald from steam at 100 °C is usually worse than a scald from the same mass of water at 100 °C. Suggest why, using ideas about energy and changes of state. [2]

Two sealed steel cylinders, A and B, have the same volume. Each contains the same number of oxygen molecules. Cylinder A is at 25 °C and cylinder B is at 100 °C.

1. (a) Compare the average speed of the molecules in A and B. [1]
2. (b) Predict which cylinder has the higher pressure. Explain your answer. [3]
3. (c) A cylinder of compressed gas carries the warning 'Do not store near a heat source'. Use your answers to explain this warning. [1]

A student puts crushed ice at −10 °C into a beaker and heats it with a Bunsen burner. She stirs and records the temperature every minute until the water has boiled for a few minutes.Time / min | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11Temperature / °C | −10 | −2 | 0 | 0 | 0 | 14 | 35 | 56 | 76 | 95 | 99 | 99

1. (a) State the time interval during which the ice was melting. [1]
2. (b) The water boiled at 99 °C instead of 100 °C. Suggest two reasons for this. [2]
3. (c) The temperature did not change between 2 and 4 minutes, although the burner was heating the beaker the whole time. Explain why. [1]
4. (d) Explain why the student stirred the mixture. [1]

1. (a) A sample of a substance is heated from −50 °C to 150 °C. It melts at −20 °C and boils at 80 °C. Describe the changes to the arrangement, movement and energy of the particles during the whole process. [4]

1. (a) A crystal of purple potassium manganate(VII) is placed at the bottom of a beaker of still water. After an hour the purple colour has spread through all the water. Name the process that spreads the colour. [1]
2. (b) Explain how the colour spreads, in terms of particles. [2]
3. (c) Predict how the time taken would change if the water were warmer. Give a reason. [1]

1. (a) Equal amounts of four gases are released at the same time in the corner of a room. Which gas spreads across the room fastest at the same temperature?A carbon dioxide, CO₂B hydrogen, H₂C methane, CH₄D nitrogen, N₂ [1]

1. (a) A teacher sprays air freshener at the front of a classroom. Students at the back smell it a short time later, although the air is still. Explain why. [2]
2. (b) Explain why the smell takes longer to reach the back of the room on a cold winter morning. [1]

A glass tube 100 cm long is clamped horizontally. A cotton wool plug soaked in concentrated ammonia solution is pushed into one end, and a plug soaked in concentrated hydrochloric acid into the other end, at the same time. Both ends are then sealed with bungs. After a few minutes a white ring of solid forms inside the tube, 59 cm from the ammonia end.[Mr: NH₃, 17; HCl, 36.5]

1. (a) Name the white solid and write the equation for its formation. [2]
2. (b) Calculate the distance of the ring from the hydrochloric acid end. [1]
3. (c) Explain why the ring forms nearer to the hydrochloric acid end. [2]
4. (d) Suggest why the tube is sealed with bungs. [1]

1. (a) A drop of green food colouring is placed in a glass of water, and a drop of bromine vapour is released into a jar of air. Both jars are at the same temperature. Which spreads out faster, the colouring in water or the bromine in air? Explain. [3]
2. (b) State one way to make the colouring spread faster in the water without stirring. [1]

A student places a crystal of a blue copper(II) salt at the bottom of a tall jar of jelly (agar). She measures how far the blue colour has travelled upwards at intervals.Time / min | 0 | 5 | 10 | 15 | 20Distance / mm | 0 | 9 | 14 | 18 | 21

1. (a) Calculate the average rate of spreading over the whole 20 minutes, in mm per minute. [1]
2. (b) Calculate the average rate of spreading in the first 5 minutes. [1]
3. (c) Suggest why the rate of spreading decreases as time goes on. [1]
4. (d) Suggest why jelly is used instead of water for this experiment. [1]

The experiment with a long tube and cotton wool plugs is repeated. This time the plug at one end is soaked in concentrated ammonia and the plug at the other end in concentrated hydrobromic acid, which gives off hydrogen bromide gas, HBr. A white solid, ammonium bromide, forms where the gases meet.[Ar: H, 1; N, 14; Br, 80]

1. (a) Calculate the relative molecular masses of NH₃ and HBr. [1]
2. (b) Predict where the white solid forms, compared with the ring formed with ammonia and hydrogen chloride (Mr 36.5) in a tube of the same length. Explain your answer. [2]
3. (c) Write the equation for the formation of ammonium bromide. [1]

A porous pot (unglazed clay, through which gases can pass) is filled with air and closed with a bung. A glass tube from the bung dips into a beaker of coloured water. A large beaker filled with hydrogen is lowered over the pot. Bubbles come out of the bottom of the tube into the water.

1. (a) Explain why bubbles come out of the tube. [3]
2. (b) The hydrogen beaker is removed. Predict what happens to the coloured water in the tube. Explain. [2]