Unit 5: Chemical Formulas and Reactions

Question 1

cation

Answer 1

an ion with a positive (+) charge

Question 2

anion

Answer 2

an ion with a negative (-) charge

Question 3

monatomic ion

Answer 3

substances that consist of single atoms

Question 4

polyatomic ion

Answer 4

a tightly bound group of atoms that has a positive or negative charge and behaves as a unit

Question 5

binary compound

Answer 5

a compound composed of 2 elements; can be either ionic or molecular

Question 6

mole

Answer 6

6.02 x 10^23 representative particles of a substance

Question 7

Avogadro’s number

Answer 7

6.02 x 10^23

Question 8

molar mass

Answer 8

the mass of a mole of an element

-the atomic mass of the element expressed in grams

Question 9

empirical formula

Answer 9

the basic formula that gives the lowest whole-number ratio of the atoms of the elements in a compound

Question 10

molecular formula

Answer 10

the chemical formula of a molecular compound

Question 11

combination reaction

Answer 11

a chemical change in which 2+ substances react to form a single new substance

Question 12

decomposition reaction

Answer 12

a chemical change in which a single compound breaks down into 2+ simpler products

Question 13

Differentiate between the five types of reactions.

Answer 13

combination, decomposition, single-replacement, double-replacement, and combustion

Question 14

Why do chemists use a systematic approach to naming compounds?

Answer 14

to be able to describe the compound using the name (water vs dihydrogen monoxide)

Question 15

What is the mole-volume relationship (pages 300-301)?

Answer 15

1 mole of a gas (at STP) = 22.4 L

Question 16

How do you determine the charge of a cation formed from a metal of Group 1A, 2A, or 3A.?

Answer 16

Group 1A= 1+
Group 2A= 2+
Group 3A= 3+

Question 17

How do you name monatomic ions?

Answer 17

+cations (mainly metals)= element ion/cation

-anions (usually nonmetals)= stem of element -ide

Question 18

What are the polyatomic ions from Table 9.3 on page 257?

Answer 18

(charts are on phone)

Question 19

What are the prefixes used when naming binary molecular compounds (Table 9.4, page 269)?

Answer 19

1 = mono-
2 = di-
3 = tri-
4 = tetra-

Question 20

How do you write formulas for ionic compounds and covalent compounds when given the name?

Answer 20

(flow charts are on phone)

Question 21

How do you write formulas and names for acids and bases?

Answer 21

(chart on phone for acid names and formulas)

-bases are named just like inonic compounds, (flow chart on phone)

Question 22

What is the general formula for an acid?

Answer 22

H˅(n)X

Where n is the number of Hydrogen (H) ions and X is a monatomic or polyatomic anion

Question 23

How do you balance a chemical equation?

Answer 23

you add coefficients to the equation so that the number of atoms in equals the number of atoms out

Question 24

How do you write balanced net ionic equations?

Answer 24

ions that appear unchanged on both sides of an equation and don’t directly participate in the reaction can be crossed out
*similar to removing like terms in an algebraic equation

Question 25

Calculate the percent composition of a compound.

Answer 25

% mass of element = (mass of element/mass of compound)* 100%