Question

Which is the process by which a gas changes to a solid?

deposition
evaporation
freezing
sublimation


Which is most likely a physical change?

cutting a substance into four pieces
burning a substance into ash and smoke
reacting a substance chemically to form a new substance
combining a substance with water to make rust


During which change of state do atoms lose energy?

sublimation
freezing
boiling
melting



View the image of a paper clip in a bowl of water.


Which best explains why this paper clip stays afloat on top of the water?

The paper clip is less dense than water.
The paper clip has less mass than water.
The water has high viscosity.
The water has surface tension.

Answer 1

1) deposition — gas turns directly into a solid.

2) cutting a substance into four pieces — this only changes shape/size (physical), not chemical identity.

3) freezing — when a liquid becomes a solid the atoms/molecules lose energy (release heat).

4) The water has surface tension — the surface tension lets the paper clip stay on top despite the clip being denser than water.