CHEM 101 Ch. 3 Matter and Energy

Question 0

What are the three states of matter?

Answer 0

solid, liquid and gas

Question 1

Define matter and list some examples.

Answer 1

Matter is defined as anything that occupies space and possesses mass. It can be thought of as the physical material that makes up the universe.

Question 2

What is the difference between crystalline solid and an amorphous solid?

Answer 2

Crystalline: atoms arranged in repeating geometric patterns

Amorphous: atoms have no long-range order

Question 3

What is a mixture?

Answer 3

Two or more pure substances combined in variable proportions.

Question 4

What is a pure substance?

Answer 4

A substance composed of only one type of atom or molecule

Question 5

What is the difference between a mixture and a compound?

Answer 5

Mixture: formed from two or more pure substances mixed together

Compound: two or more elements bonded together to form a new substance

Question 6

What is the difference between a physical change and a chemical change?

Answer 6

Physical change: composition of the substance does not change, even if appearance changes

Chemical change: substance undergoes a change in its composition

Question 7

What is the definition of energy?

Answer 7

Energy is defined as the capacity to do work.

Question 8

Explain the difference between kinetic energy and potential energy?

Answer 8

Kinetic energy: energy of movement

Potential energy: energy associated with position or composition of a substance.

Question 9

Classify each pure substance as an element or a compound.

a. Aluminium
b. Sulfur
c. Methane
d. Acetone

Answer 9

a. element
b. element
c. compound
d. compound

Question 10

Classify each mixture as homogenous or heterogenous.

a. coffee
b. chocolate sundae
c. apple juice
d. gasoline

Answer 10

a. homogenous
b. heterogenous
c. homogenous
d. homogenous

Question 11

Classify each substance as a pure substance or a mixture. If it is a pure substance, classify it as an element or a compund. If it is a mixture, classify it as a homogenous or heterogenous mixture.

a. helium gas
b. clean air
c. rocky road ice cream
d. concrete

Answer 11

a. pure substance - element
b. mixture - homogenous
c. mixture - heterogenous
d. mixture - heterogenous

Question 12

Classify each property as physical or chemical.

a. the tendency of silver to tarnish
b. the shine of chrome
c. the color of gold
d. the flammability of propane gas

Answer 12

a. chemical
b. physical
c. physical
d. chemical

Question 13

The following list contains several properties of ethylene (a ripening agent for bananas). which are physical properties, and which are chemical properties?
• colorless
• odorless
• flammable
• gas at room temperature
• 1 L has a mass of 1.260 g under standard conditions
• mixes with acetone
• polymerized to form polyethylene

Answer 13

• colorless - physical
• odorless - physical
• flammable - chemical
• gas at room temperature - physical
• 1 L has a mass of 1.260 g under standard conditions - physical
• mixes with acetone - physical
• polymerized to form polyethylene - chemical

Question 14

Determine whether each change is physical or chemical.

a. A balloon filled with hydrogen gas explodes upon contact with a spark.
b. The liquid propane in a barbecue evaporates away because the user left the valve open
c. The liquid propane in a barbecue ignites upon contact with a spark
d. Copper metal turns green on exposure to air and water.

Answer 14

a. chemical
b. physical
c. chemical
d. chemical

Question 15

A block of aluminum is (a) ground into aluminum powder and then (b) ignited. It then emits flames and smoke. Classify (a) and (b) as chemical or physical changes.

Answer 15

a. physical

b. chemical