3 - Matter and Energy

Question 1

How is matter defined?

Answer 1

Anything that has mass and takes up space

Question 2

What do the atoms and molecules do in solid matter?

Answer 2

They tightly pack themselves in fixed locations

Question 3

Which type of solid has atoms that arrange themselves in long-range geometric patterns?

Answer 3

Crystalline solids

Question 4

Which type of solid has atoms that do not have long range order?

Answer 4

Amorphous solids

Question 5

Give an example of a crystalline solid

Answer 5

Diamond, salt

Question 6

Give an example of an amorphous solid

Answer 6

Plastic, glass

Question 7

How do atoms behave in liquid matter?

Answer 7

They are in close proximity but can move freer than atoms in solid matter

Question 8

How do atoms behave in gaseous matter?

Answer 8

They are separated by large distances and are very free to move around

Question 9

Why are gases compressible?

Answer 9

The atoms are not in contact with one another, unlike solids or liquids

Question 10

What is a pure substance?

Answer 10

Matter that is only composed of one type of atom or molecule

Question 11

What is a mixture?

Answer 11

Matter that is composed of two or more different types of atoms or molecules in varying proportions

Question 12

Which groups can pure substances be divided into?

Answer 12

Elements and compounds

Question 13

Describe an element

Answer 13

A substance that cannot be broken down into simpler substances

Question 14

Describe a compound

Answer 14

A substance composed of two or more elements in fixed definite proportions

Question 15

Are compounds or elements more common in everyday life? Why?

Answer 15

Compounds; most elements are chemically reactive and often combine with other elements to form compounds

Question 16

What is the difference between a mixture and a compound?

Answer 16

A mixture is a mix of two or more types of atoms with varying proportions in each sample. A compound is a mix of two or more types of atoms with the same fixed definite proportions in each sample.

Question 17

Which groups can mixtures be divided into?

Answer 17

Heterogenous and homogenous

Question 18

Describe a heterogenous mixture

Answer 18

A mixture in which the composition varies from one region to another, such as oil in water

Question 19

Describe a homogenous mixture

Answer 19

A mixture in which the composition is uniform throughout, such as coffee

Question 20

Classify: Lead weight

Answer 20

Pure substance, element (lead is on the periodic table),

Question 21

Classify: Seawater

Answer 21

Mixture, homogenous (it has a uniform composition)

Question 21

Classify: Italian salad dressing

Answer 21

Mixture, heterogenous

Question 21

Classify: Distilled water

Answer 21

Pure substance, compound (it is a compound because distilled water is not on the periodic table)

Question 22

What is a physical property?

Answer 22

One that a substance displays without changing its composition

Question 23

Why is the odor of gasoline a physical property?

Answer 23

Gasoline does not have to change its chemical composition to exhibit the odor

Question 24

What is a chemical property?

Answer 24

One that a substance displays only through changing its composition

Question 25

Examples of physical properties

Answer 25

Color, taste, odor, appearance, melting/boiling points, density

Question 26

Why is the flammability of gasoline a chemical property?

Answer 26

Gasoline changes its composition when it burns

Question 26

Examples of chemical properties

Answer 26

Corrosiveness, flammability, acidity, and toxicity

Question 27

Classify: Copper turning green when exposed to air

Answer 27

Chemical property; the copper reacts with gases in the air

Question 28

Classify: Automobile paint dulling over time

Answer 28

Chemical property; the paint reacts with sunlight or with oxygen in the air

Question 29

Classify: Gasoline evaporating quickly when spilled

Answer 29

Physical property; the gasoline has a low boiling point, causing quick evaporation

Question 30

Classify: low mass of aluminum compared to other metals

Answer 30

Physical property

Question 31

What is a physical change?

Answer 31

Matter changes its appearance, but not its composition

Question 32

How is ice melting an example of a physical change?

Answer 32

The ice melts into water; only the appearance has changed but the H2O molecules are still present

Question 33

What is a chemical change?

Answer 33

When matter has to change its composition

Question 34

How is copper turning green a chemical change?

Answer 34

Copper turns green because it reacts with gases in the air to form new compounds

Question 35

What does a chemical reaction diagram look like?

Answer 35

Reactants -----------> Products

Question 36

Classify: The rusting of iron

Answer 36

Chemical change; Iron reacts with oxygen in the air to form iron oxide

Question 37

Classify: Evaporation of acetone (nail polish remover) from the skin

Answer 37

Physical change; the acetone goes from liquid to gas, but is still acetone

Question 38

Classify: The burning of coal

Answer 38

Chemical change; Coal burns as it reacts with oxygen in the air to form carbon dioxide

Question 39

Classify: The fading of a carpet upon repeated exposure to sunlight

Answer 39

Chemical change; The molecules that give the carpet its color are decomposed by the sunlight

Question 40

Define immiscible

Answer 40

Substances that do not mix (oil and water)

Question 41

Define decanting

Answer 41

the separation of immisicible liquids

Question 42

Define distillation

Answer 42

separating miscible substances by heating the more volatile liquid

Question 43

Law of conservation of mass

Answer 43

Matter is neither created nor destroyed in a chemical reaction

Question 43

Define volatile

Answer 43

more easily vaporizable

Question 44

Practice: 58 g of butane is burnt in a lighter. It reacts with 208 g of oxygen to form 176 g of carbon dioxide and 90 g of water. How much matter is in the reactants and how much is in the products?

Answer 44

266 g in both reactants and products

Question 45

Define energy

Answer 45

The capacity to do work

Question 46

Define work

Answer 46

The result of a force acting on a distance

Question 47

Law of conservation of energy

Answer 47

Energy is neither created nor destroyed

Question 48

Kinetic energy

Answer 48

Energy associated with motion

Question 49

Potential energy

Answer 49

energy associated with its position or composition

Question 50

Thermal energy

Answer 50

energy associated with random motions of atoms and molecules in matter

Question 50

Chemical energy

Answer 50

form of potential energy, associated with positions of particles that compose the chemical system

Question 51

Electrical energy

Answer 51

associated with the flow of electrical charge

Question 52

Physical and chemical changes are usualy accompanied by....

Answer 52

energy changes

Question 53

Endothermic reactions

Answer 53

Chemical reactions that absorb energy from their surroundings as they occur

Question 54

Exothermic reactions

Answer 54

Chemical reactions that release energy as they occur