In which changes do the particles move further apart?
W and X
W and Z
X and Y
Y and Z
Which change of state takes place during evaporation?
A gas to liquid
B liquid to gas
C liquid to solid
D solid to gas
In which process do particles move closer together but remain in motion?
condensation
diffusion
evaporation
freezing
The changes that occur when a substance changes state are shown at the right.
Which process, W, X, Y or Z, is occurring in the following four situations?
1 Butter melts on a warm day. 2 Water condenses on a cold surface. 3 The volume of liquid ethanol in an open beaker reduces. 4 Ice forms inside a freezer.
A
B
C
D
The diagram shows a sugar lump in a cup of tea.
Which two processes must happen to spread the sugar evenly in the tea?
First process = diffusion; Second process = dissolving
First process = dissolving; Second process = diffusion
First process = dissolving; Second process = melting
First process = melting; Second process = diffusion
A sugar cube is dropped into a hot cup of tea. The tea is not stirred.
Which statement explains why the tea becomes sweet?
A The heated water molecules penetrate the sugar cube.
B The hot tea causes the sugar to melt.
C The sugar cube dissolves and its molecules diffuse.
D The sugar molecules get hot and evaporate.
A crystal of purple potassium manganate(VII) was added to each of the beakers shown in the diagram.
One beaker contained hot water and the other beaker contained cold water.
In both beakers the purple colour of the potassium manganate(VII) spreads out.
Which result and explanation are correct?
Which statement is an example of diffusion?
A A kitchen towel soaks up some spilt milk.
B Ice cream melts in a warm room.
C Pollen from flowers is blown by the wind.
D The smell of cooking spreads through a house.
A few drops of perfume were spilt on the floor. A few minutes later the perfume could be smelt a few metres away.
Which two processes had taken place?
A distillation and condensation
B distillation and diffusion
C evaporation and condensation
D evaporation and diffusion.
Two gas jars each contain a different gas. The gas jars are connected and the cover slips are removed. The diagram shows what happens to the particles of the gases.
Which process has occurred?
A Chemical reaction
B Condensation
C Diffusion
D Evaporation
A liquid is heated until it boils.
Which result shows that the liquid in the test-tube is pure water?
A Condensation occurs at the top of the test-tube.
B Steam is produced.
C Thermometer reads 100 oC.
D There is nothing left behind in the test-tube.
An attempt was made to compress a gas and a solid using the apparatus shown.
Which substance would be compressed and what is the reason for this?
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