Unit 8

Question 1

What are chemical reactions represented by?

Answer 1

Chemical equations. In a chemical equation there is a reactant and a product.
Reactant –> Product

Question 2

In a chemical reaction, atoms are

Answer 2

Neither created nor destroyed which means the reactant and product sides of the equation have the same number of each atoms.

Question 3

What does “(s)” symbol stand for in a balanced equation? (Shows up as a subscript next to the amount of element)

Answer 3

Solid

Question 4

What does “(l)” symbol stand for in a balanced equation? (Shows up as a subscript next to the amount of element)

Answer 4

Liquid

Question 5

What does “(g)” symbol stand for in a balanced equation? (Shows up as a subscript next to the amount of element)

Answer 5

Gas

Question 6

What does “(aq)” symbol stand for in a balanced equation? (Shows up as a subscript next to the amount of element)

Answer 6

Aqueous (dissolved in water)

Question 7

What should you change when balancing equations?

Answer 7

The coefficients and NEVER the subscripts.
Coefficients are never in the middle of a molecule, always in the front.

Question 8

What are the naturally diatomic elements?

Answer 8

Bromine, Iodine, Nitrogen, Chlorine, Hydrogen, Oxygen, Fluorine.
HI BrO FNCl

Question 9

Synthesis reaction

Answer 9

A reaction where two or more reactants form ONE product.

Question 10

Decomposition reaction

Answer 10

A r.eaction where ONE reactant produces two or more products

Question 11

Single replacement reaction

Answer 11

element + compound —> element + compound
One element and one compound on each side.

Question 12

Double replacement reaction

Answer 12

compound + compound —> compound + compound
two compounds on each side. The elements of the compounds switching places

Question 13

Combustion reaction

Answer 13

A reaction with oxygen.
Hydrocarbon + O2 —> CO2 + H2O

Question 14

Neutralization reaction

Answer 14

Acid-Base reaction. When an acid (H+) and a base (OH-) react to form water.
Water is in the products.

Question 15

Oxidation-Reduction reaction

Answer 15

Transfer of electrons (change in electron structure of the ions or atoms involves)
Any reaction where an atom is unbonded on one side and bonded on the other.
ALWAYS single replacement
NEVER double replacement

Question 16

Oxidation is…

Answer 16

Loss of electrons (becoming more positive)

Question 17

Reduction is…

Answer 17

Gain of electrons (becoming more negative)

Question 18

What is stoichiometry?

Answer 18

Defined as the quantitative relationship between two or more substances especially in processes involving physical or chemical change.

Question 19

Steps to solving ANY stoichiometry problem?

Answer 19

1. BALANCE the equation
2. Convert given to MOLES
3. Convert from one molecule to another using moles to moles
4. Convert to what is being asked for

Question 20

How to find percent yield?

Answer 20

(actual yield / theoretical yield) 100

Question 21

Theoretical yield is…

Answer 21

grams unless otherwise stated

Question 22

What is the limiting reactant?

Answer 22

The reactant that is least in amount.

Question 23

How to find the excess reactant? (once the limiting reactant is used up what is left of the other reactants?)

Answer 23

Using the limiting reactant as the GIVEN (of a stoichiometry problem) and the other reactant as what you want to solve for.