Chemistry

Question 1

What is the process of which a substance goes from solid to gas? (without becoming a liquid)

Answer 1

Sublimation

Question 2

What is the process of which a substance goes from a gas to a solid? (without becoming a liquid)

Answer 2

Desublimation AND/OR Deposition

Question 3

What are attractive forces?

Answer 3

The forces of which attract particles together. (usually in solids)

Question 4

When a solid has melted into a liquid, what happens to the attractive forces?

Answer 4

MOST of the attractive forces have been overcome.

Question 5

What is an exothermic change in a reaction?

Answer 5

Energy is transferred TO the surroundings

energy EXits the reaction

Question 6

What is an endothermic change in a reaction?

Answer 6

Energy is transferred FROM the surroundings

energy ENters the reaction

Question 7

What happens at the melting point or boiling point of a PURE substance? and WHY?

Answer 7

The M.P or B.P occurs at a single temperature.

There is only one substance in a pure substance and therefore it has only one melting point.

Question 8

What happens at the melting point or boiling point of an IMPURE substance? and WHY?

Answer 8

The M.P or B.P occurs at several different temperatures.

Because each substance substances inside of it have different melting points.

Question 9

What are the 3 main processes of Water Purification and how does it work?

Answer 9

1. Sedimentation (water is left to settle to the bottom of the water tank)
2. Filtration (the water is filtered through several different methods)
3. Chlorination (a small concentration of chlorine is put inside of the water to kill the final remaining potentially harmful microorganisms inside of it)