Question

prepwork:
for each question below, use the annotation techniques practiced in class before choosing your final
answer. after annotating, write your final answers in the grid below.
answers:

1. 2. 3. 4. 5.
2. **two basic properties of the gas phase are

a. a definite shape and a definite volume
b. a definite shape but no definite volume
c. no definite shape but a definite volume
d. no definite shape and no definite volume

1. **which terms are used to identify pure substances?

a. an element and a mixture
b. an element or a compound
c. a solution and a mixture
d. a solution and a compound

1. **which set of procedures and observations indicates a chemical change?

a. ethanol is added to an empty beaker and the ethanol eventually disappears.
b. a solid is gently heated in a crucible and the solid slowly turns to a liquid.
c. large crystals are crushed with a mortar and pestle and become powder.
d. a cool, shiny metal is added to water in a beaker and rapid bubbling occurs.

Explanation:

1. Question 1:

• Gases have no definite shape (they take the shape of their container) and no definite volume (they expand to fill the container).

1. Question 2:

• A pure substance is either an element (made of one type of atom) or a compound (made of two or more types of atoms chemically combined). A mixture is not a pure substance.

1. Question 3:

• A chemical change produces a new substance. When a metal reacts with water and there is rapid bubbling (indicating a gas is produced, a new substance), it is a chemical change. Options a (evaporation), b (melting), and c (physical crushing) are physical changes.

Answer:

1. d
2. b
3. d