1. 
Fill in the blank:

The reverse of melting is called : a liquid turns back into a solid at exactly the same temperature.

2. 
According to the text, what happens to evaporation when the surface area of a liquid is made larger?

3. 
True or False: The melting point and the freezing point of a pure substance are the same temperature.

4. 
Which term describes a change of state where a solid turns directly into a gas, without becoming a liquid first?

5. 
Fill in the blank:

Solid carbon dioxide is often called "dry " because it turns straight into a gas without leaving a liquid film on the surface.

6. 
Fill in the blank:

In the thermal conductivity test, candles are fixed to a metal rod and a rod; both are heated from one end, and the candles on the metal rod fall off first.

7. 
Fill in the blank:

Ethanol has a lower boiling point than water, so ethanol is more than water.

8. 
True or False: Boiling happens only at the surface of a liquid, while evaporation happens throughout the whole liquid.

9. 
True or False: In the hardness test, a diamond can scratch a steel sheet, but steel cannot scratch the diamond.

10. 
Fill in the blank:

Iron, cobalt, nickel and neodymium are all attracted by a magnet; substances with this property are described as .

11. 
Fill in the blank:

A substance that consists of only one substance, without any contaminating impurities, is called a substance.

12. 
Fill in the blank:

When sugar is placed in water it slowly disappears, but a metal spoon does not; this property, which helps identify substances, is called .

13. 
In the electrical conductivity test with a battery, wire and LED, what happens when the object being tested is a plastic comb?

14. 
Why does seawater freeze below 0°C and boil above 100°C, unlike pure water?