States of Matter (Edexcel GCSE Chemistry)

Which of the following substances will be a solid at 20C and will melt when placed in a beaker of hot water at 80C?  

A student set up the apparatus shown in Figure 4 to obtain pure water from sea water by distillation.

Figure 4

i) Explain how the water in sea water separates to produce the pure water in this apparatus.

(2)

ii) Explain how the apparatus could be improved to increase the amount of pure water collected from the same volume of sea water.

(2)

A substance is heated at a constant rate and its temperature is taken every minute. During the heating, the substance undergoes one change of state. The results are shown on the graph in Figure 5.

Figure 5

Explain the shape of the graph in terms of the changes in the movement and arrangement of the particles as the substance is heated.

Substances exist as solids, liquids or gases.

What change of state occurs at Y? 

Substance Y melts at -101 ^oC and boils at -35 ^oC.

What is the state of substance Y at at -110 ^oC? 

If liquid water is cooled below 0°C it turns into the solid, ice.

i) Give the name for the change of state from liquid to solid.

(1)

ii) Here are five statements about ice and water.

Place ticks in boxes by the two statements that are correct.

(2)

Figure 2 shows a label from a bottle of drinking water.

Figure 2

i) Explain why this drinking water should not be described as pure water.

(2)

ii) State the information from Figure 2 that shows that the drinking water is neutral.

(1)

iii) Calculate the mass of calcium ions in 250 cm³ of this drinking water.

(2)

mass = .............................................................. mg

State how you know that calcium is a metal from its position in the periodic table.

Solids, liquids and gases have different properties due to the arrangement of their particles.

Which statement is not a property of a liquid?

Substance Z has a melting point of -7 ^oC and boiling point of 59 ^oC. 

What is the state of Z at 0 ^oC and 100 ^oC?  

Which of the following is not a chemical change?

The table gives the melting and boiling points of four pure substances, W, X, Y and Z.

Use data from the table to answer the questions.

i) Which substance is a gas at 100 °C?

(1)

ii) Which substance is a liquid for the largest range of temperature?

(1)

iii) Which substance is a liquid at 1000 °C and a gas at 2000 °C?

(1)

Substance Y does not conduct electricity when solid but does conduct electricity when molten.

Give the type of bonding in substance Y.

Suggest how the melting point of a pure substance changes when an impurity is added.

A mixture containing substance W is purified using the equipment shown in Figure 1.

 Figure 1

Explain how this technique works by referring to the energy and arrangement of the particles during the physical changes that occur.

Figure 1 shows how the temperature of a substance that starts off as a gas changes as it is cooled at a constant rate.

Figure 1

Use Figure 1 to identify:

i) The melting point of the substance.

[1]

ii) The boiling point of the substance.

[1]

Give the state of the substance at:

i) 0°C

[1]

ii) 120°C

[1]

Calculate how long it took for the liquid to completely change into a solid.

Describe what happens to the energy, movement and arrangement of particles as a substance condenses.

Air is a mixture of gases.

Figure 1 shows the boiling points for the main gases in the air.

Figure 1

The gases in air can be separated in an industrial process.

In the first step the air is cooled to turn it into a liquid.

State the minimum temperature needed for this. Give a reason for your answer.

Then, the liquid air is slowly heated to separate the gases.

State how to separate only nitrogen from the liquid air.

Nitrogen is a reactant in the Haber process to make ammonia.

The reaction is reversible. The symbol equation for the reaction is:

2N₂ (g) + 3H₂ (g) ⇌ 2NH₃ (g)

The gaseous ammonia is turned into a liquid as soon as it is made.

Suggest how this is done.

Higher Tier Only

Explain why ammonia is turned into a liquid as soon as it is made.

Give your answer in terms of equilibrium.

The alkanes are a homologous family of hydrocarbons.

Figure 1 shows information about some of the alkanes.

Figure 1

Name the alkane that is a liquid at room temperature (20°C).

State the empirical formula of butane.

Describe the relationship between length of alkane and boiling point.

Suggest a reason for this relationship.

Dry ice is solid carbon dioxide.

In the box below draw the arrangement of particles in dry ice.

Solid carbon dioxide changes straight into a gas. This happens at -78.5°C.

Name this interconversion of state.

Compare the energy of the particles in dry ice compared to the particles in gaseous carbon dioxide.

A piece of dry ice is added inside an empty balloon. The neck of the balloon is sealed.

Describe what you would see happening.

Give a reason for your answer.