Ch. 2: A Review of Basic Chemistry

Question 1

Chemistry

Answer 1

The study of matter and the changes it undergoes

Question 2

Atoms

Answer 2

The fundamental building blocks of matter

Question 3

Protons

Answer 3

Positively charged and have a mass of approximately 1 atomic mass unit (amu).

Question 4

Atomic number (Z)

Answer 4

The number of protons and determines the identity of the atom. Usually, represented by Z.

Question 5

Neutrons

Answer 5

Electrically neutral and have a mass of approximately 1 amu

Question 6

1 amu =

Answer 6

1.66 x 10^27 kg

Question 7

Electrons

Answer 7

Negatively charged and have a much smaller mass than either protons or neutrons

Question 8

Ions

Answer 8

Atoms or groups of atoms bonded together that have anet electrical charge. This charge is attained by adding or removing electrons.

Question 9

Cations vs Anions

Answer 9

Cations have a positive electrical charge. Anions have a negative electrical charge.

Question 10

Mnemonic for cation vs. anion

Answer 10

A Negative Ion = ANION

PAWSitive = CATION (cats have paws)

Question 11

Elements

Answer 11

Comprised of only one kind of atom

Question 12

Compounds

Answer 12

Comprised of more than one kind of atom in a fixed ratio by mass

Question 13

Molecules (or molecular compounds)

Answer 13

Group of atoms chemically bonded together into a discrete unit by covalent bonds. Molecules are electrically neutral.

Question 14

Ionic compounds

Answer 14

Contain positive and negatively charge ions.

Question 15

Can a substance be a molecule and a element?

Answer 15

Yes. O2 consists of 2 oxygen atoms bonded together to form an oxygen molecule. But oxygen is also an element because it contains only oxygen atoms.

Question 16

Example of an element vs. compound

Answer 16

O2 or He vs. H20

Question 17

Atom, Molecule, Compound

Answer 17

He
O2
H20

Question 18

Chemical changes (physical vs. chemical)

Answer 18

Can be physical or chemical. Physical changes occur without changing the chemical makeup of a substance changing. Chemical changes always result in the formation of chemically different substances.

Question 19

Physical vs chemical change example

Answer 19

Physical: Ice cube melting to water. Water is just changing from a solid to liquid form.
Chemical: If we run an electric current through water (containing a small amount of an electrolyte, sodium sulfate), the water will break down into hydrogen gas and oxygen gas

Question 20

Mixtures

Answer 20

It is comprised of two or more pure substances.

Question 21

Homogenous mixture

Answer 21

Uniform in chemical and physical properties through the sample (e.g., NS)

Question 22

Heterogenous mixture

Answer 22

Exhibits distinct phase boundaries between its components. A phase boundary is a demarcation where the chemical and/or physical properties of the sample change (e.g., emesis).