States of Matter (Edexcel IGCSE Science (Double Award): Chemistry)

This question is about states of matter.

The diagram shows how the particles of a substance are arranged in two different states.

i) Complete the diagram to show how particles are arranged in the liquid state.

 (1)

ii) Identify the state of matter in which the particles have the most energy.

(1)

The state symbols (s), (l), (g) and (aq) are often used in chemistry. The table shows some physical changes. Complete the table by giving the state symbol before and after each change.

Explain why hot water evaporates more quickly than cold water.

This question is about ammonium chloride.

Give the formula of the ammonium ion.

Describe a test to show that ammonium chloride contains ammonium ions.

The equation shows the thermal decomposition of ammonium chloride.

NH₄Cl(s)  NH₃(g) + HCl(g)

State what the symbol indicates about this reaction.

The diagram shows the formation of ammonium chloride in a glass tube.

i) Explain how the mean speed of ammonia molecules compares with the mean speed of hydrogen chloride molecules.

(2)

ii) Gas particles travel very quickly. Give two reasons why it takes several minutes for the ammonium chloride to form.

(2)

The boxes list changes that may happen in a laboratory and the names of some changes.

 Draw one straight line from each change to its correct name.

A student has two solids, X and Y.

One of these solids is a pure substance and the other is a mixture.

Describe how the student could identify which solid is pure and which is a mixture by measuring a physical property of each solid.

This question is about states of matter.

Use the words solid, liquid or gas to give the initial and final state of matter for each of the changes listed in the table. The first one has been done for you.

Particles in a solid are closely packed, arranged in a regular pattern and vibrate about fixed positions.

Describe the arrangement and movement of the particles in a gas.

Some sugar is added to cold water in a beaker.

After some time, all the sugar dissolves and spreads throughout the water.

i) Name the process that occurs that causes the sugar to spread throughout the water.

(1)

 ii) State two ways to make the sugar dissolve more quickly.

(2)

Pure water can be obtained from the sugar solution using this apparatus.

 i) Name the process used to obtain pure water from the sugar solution.

(1)

 ii) Explain the purpose of the piece of apparatus labelled X.

(2)

This question is about states of matter.

The box gives words relating to changes of state.

 Complete the table by giving the correct word from the box for each change of state.

When ammonia gas and hydrogen chloride gas mix, they react together to form a white solid called ammonium chloride.

 The equation for the reaction is

 NH₃ (g) + HCl (g) → NH₄Cl (s)

 A teacher soaks a piece of cotton wool in concentrated ammonia solution and another piece of cotton wool in concentrated hydrochloric acid.

 The teacher places the two pieces of cotton wool at opposite ends of a glass tube at the same time.

 After several minutes, a white ring of solid ammonium chloride forms.

 i) State the name given to the spreading out of gas particles. 

(1)

ii) State how the diagram shows that the particles of ammonia gas are travelling at higher speeds than the particles of hydrogen chloride gas. 

(1)

 iii) Gas particles travel at high speeds. 

Give a reason why the white ring of ammonium chloride takes several minutes to form.

(1)

iv) Concentrated ammonia solution and concentrated hydrochloric acid are corrosive.

 Give one safety precaution the teacher should take.

(1)

i) State the meaning of the term solute.

 (1)

 ii) State the meaning of the term solvent.

 (1)

Explain what is meant by a saturated solution.

A dark purple liquid is diluted by adding water. 

The diluted liquid becomes a pale purple colour. 

Explain the process that causes this change. 

Refer to particles in your answer.

Substances can exist as solids, liquids or gases.

i) Give the change of state that occurs when a substance melts.

(1)

ii) Complete the word equation for the sublimation of iodine.

iodine (s) → iodine (...........)

(1)

The circle in the diagram represents a particle. Complete the diagram to show the arrangement of particles in a gas.

The table lists some statements about particles. Place ticks (✔) in boxes to show which two statements are correct for water particles.