Chemistry Test #1

Question 1

What are the TWO characteristics of matter?

Answer 1

It has mass and occupies space

Question 2

What is the smallest complete unit of matter?

Answer 2

Atom

Question 3

Difference between pure substances and mixtures?

Answer 3

a pure substance consists only of one element or one compound. a mixture consists of two or more different substances, not chemically joined together.

Question 4

Difference between an element and a compound?

Answer 4

Element: Pure substance consisting of one type of atom. Compound: Pure substance consisting of two or more different atoms.

Question 5

Difference between homogenous and heterogenous mixtures?

Answer 5

Heterogeneous mixtures have visually distinguishable components, while homogeneous mixtures appear uniform throughout

Question 6

What is another name for a homogeneous mixture?

Answer 6

Solution

Question 7

Examples of chemical properties?

Answer 7

flammability, toxicity, acidity, reactivity (many types), and heat of combustion.

Question 8

Examples of physical properties?

Answer 8

density, color, hardness, melting and boiling points, and electrical conductivity.

Question 9

Difference between chemical and physical changes?

Answer 9

Physical changes only change the appearance of a substance, not its chemical composition. Chemical changes cause a substance to change into an entirely substance with a new chemical formula.

Question 10

A substance boils and evaporates.

Chemical or physical change.

Answer 10

Physical Change.

The substance is still made up of the same chemical composition just at a different temperature.

Question 11

Wood is chopped up and cannot be turned back into a log.

Chemical or physical change?

Answer 11

Physical change.

The wood is still the same wood, just chopped up.

Question 12

Salt dissolves in water

Answer 12

Chemical Change.

The salt dissolves in water, becoming a solution and is irreversible.

Question 13

5 signs a chemical change has happened?

Answer 13

color change, formation of a precipitate, formation of a gas, odor change, temperature change

Question 14

What are subatomic particles?

Compare them on size, location, and electric charge.

Answer 14

Protons, Neutrons, Electrons.

PROTONS- 1AMU
NUETRONS- 1AMU
ELECTRONS -0 AMU
Protons and neutrons are in the centre of the atom, making up the nucleus. Electrons surround the nucleus

Protons have a positive charge. Electrons have a negative charge. Neutrons have no charge.

Question 15

What is the Atomic number?

Answer 15

the number of protons in the nucleus of an atom

Question 16

What is the Atomic mass?

Answer 16

Mass of an atom

Question 17

How many electrons can fit in the first energy level?

Answer 17

2

Question 18

How many electrons can fit in the 2nd energy level

Answer 18

8

Question 19

How many electrons can fit in the 3rd energy level?

Answer 19

8

Question 20

How many electrons can fit in the 4th energy level?

Answer 20

18

Question 21

What is a valence electron? What does it dictate?

Answer 21

a single electron or one of two or more electrons in the outer shell of an atom that is responsible for the chemical properties of the atom

Question 22

Difference between a coefficient and a subscript?

Answer 22

Subscripts - Part of the chemical formulas of the reactants and products that indicate the number of atoms of the preceding element.

Coefficient - A small whole number that appears in front of a formula in a balanced chemical equation.

Question 23

Difference between an atom and an ion?

Answer 23

An atom has no electrical charge. Ions have an electrical charge because they have an imbalance of protons and electrons

Question 24

Difference between a cation and an anion?

Answer 24

Cations are positively charged ions

Anions are negatively charged ions

Question 25

Ionic compounds involve transfer or sharing of valance electrons?

Answer 25

Transfer

Question 26

What type of elements form ionic bonds?

Answer 26

metals and non metal ions

Question 27

Metals usually form cations or anions?

Answer 27

Cations

Question 28

Non metals usually form cations or anions?

Answer 28

Anions

Question 29

is non metal or metal written first in an ionic compound?

Answer 29

Metal

Question 30

a precipitate forms after a reaction, is it the same thing as freezing when a solid forms? why?

Answer 30

No, precipitate is chemical, freezing is physical

Question 31

How to calculate the number of protons, electrons, and neutrons in a neutral atom?

Answer 31

``` # of protons = the atomic number # of neutrons = mass # - atomic # # of electrons= # of protons in a neutral atom ```

Question 32

Difference between groups and periods?

Answer 32

groups are vertical | periods are horizontal

Question 33

How can you tell the number of valence electrons an element has

Answer 33

by what group its in

Question 34

Name this compound Mg3N2

Answer 34

Trimagnesium dinitride

Question 35

What is a polyatomic ion? How do you name them?

Answer 35

is a covalently bonded set of two or more atoms. The cation is written first in the name; the anion is written second in the name.

Question 36

What are two ways non metals can obtain a full valence shell?

Answer 36

transfer or share

Question 37

Are molecular compounds always made up of non metals?

Answer 37

yes, they share there electrons

Question 38

Can a covalent bond share multiple pairs of electrons? Example?

Answer 38

Yes, carbon dioxide

Question 39

Name this compound: PBr5

Answer 39

Phosphorus Pentabromide

Question 40

What is the formula for sulphur trioxide?

Answer 40

SO3

Question 41

What can be said about how diatomic elements occur in nature ?

Answer 41

Bonded with another of the same element

Question 42

What is combining capacity

Answer 42

Number of bonds that need to form in order to have a stable atom