Which change of state takes place during evaporation?
Respuesta
A gas to liquid
B liquid to gas
C liquid to solid
D solid to gas
Pregunta 3
Pregunta
In which process do particles move closer together but remain in motion?
Respuesta
condensation
diffusion
evaporation
freezing
Pregunta 4
Pregunta
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.
The diagram shows a sugar lump in a cup of tea.
Which two processes must happen to spread the sugar evenly in the tea?
Respuesta
First process = diffusion; Second process = dissolving
First process = dissolving; Second process = diffusion
First process = dissolving; Second process = melting
First process = melting; Second process = diffusion
Pregunta 6
Pregunta
A sugar cube is dropped into a hot cup of tea.
The tea is not stirred.
Which statement explains why the tea becomes sweet?
Respuesta
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.
Pregunta 7
Pregunta
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?
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?
Respuesta
A distillation and condensation
B distillation and diffusion
C evaporation and condensation
D evaporation and diffusion.
Pregunta 10
Pregunta
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?