Unit 7

Question 1

What is theoretical yield?

Answer 1

The maximum amount of product that can be produced from a given amount of reactant; the calculated value

Question 2

What is percent yield?

Answer 2

The ratio of the actual yield to the theoretical yield, multiplied by 100

Question 3

In stoichiometry problems, if you want your answer in moles, you do not need step ____

Answer 3

Three

Question 4

What is electrolysis?

Answer 4

The decomposition of a substance by an electric current

Question 5

What is combustion?

Answer 5

Type of reaction where a substance (usually a hydrocarbon compound) combines with oxygen, releasing a large amount of energy in the form of light & heat

Question 6

What is a coefficient?

Answer 6

Number in front of a substance in a balanced equation that tells how many are in the reaction

Question 7

In stoichiometry problems you always need step ___

Answer 7

Two

Question 8

What is excess reagent?

Answer 8

The reagent that is not completely used up in a chem. rxn.

Question 9

What is decomposition?

Answer 9

Type of reaction where a single compound (reactant) undergoes a reaction that produces 2 or more simpler substances (products)
AB—> A + B
AB is a cmpd.
A&B can be elements or cmpds.

Question 10

In stoichiometry problems, if you start with moles you do not need step ___

Answer 10

One

Question 11

When do decomposition reactions take place?

Answer 11

When energy is added, sometimes in the form of heat or electricity

Question 12

What is a chemical reaction?

Answer 12

The process by which one or more substances are changed into one or more different substances

Question 13

What is step #1 of a stoichiometry problem?

Answer 13

Converting the given quantity to moles

Question 14

What is double replacement?

Answer 14

Type of reaction where the ions of 2 compounds (reactants) exchange places in aqueous solution to from 2 new compounds (products)
AB + CD —> AD + CB
All are cmpds.

Question 15

What is activity series?

Answer 15

A list of elements organized according to the ease with which the elements undergo certain chemical reactions

Question 16

What is actual yield?

Answer 16

The measured amount of product obtained from a chemical reaction

Question 17

What is precipitate?

Answer 17

A solid that is produced as a result of a chemical reaction in a solution; it is insoluble & separates from the solution

Question 18

What is step #3 in a stoichiometry problem?

Answer 18

Convert back to the desired units

Question 19

What is step #2 of a stoichiometry problem?

Answer 19

Determine the mole to mole ratio

Question 20

What is synthesis?

Answer 20

Type of reaction where 2 or more substances (reactants) combine to form a new cmpd. (Product)
A + B —> AB
A&B can be elements or cmpds.
AB is a cmpd.

Question 21

What are reactants?

Answer 21

One or more substances (elements/compounds) start reaction with

Question 22

What is stoichiometry?

Answer 22

The calculation of the quantities of reactants & products involved in a chem. rxn.

Question 23

What is mole ratio?

Answer 23

A conversion factor derived from the coefficients of a balanced chemical equation

Question 24

What are products?

Answer 24

One or more new substances (elements/cmpds.) formed from rxn.

Question 25

What is single replacement?

Answer 25

Type of reaction where one element replaces a similar element in a cmpd. (Reactant) to form a new element & cmpd. (Products)
A + BC ---> AC + B
A + BC ---> C + BA
A & c are elements 
BC & BA are cmpds.

Question 26

What is limiting reagent?

Answer 26

The reagent that determine the amount of product that can be formed by a chem. rxn.; completely used up in a chem. rxn.

Question 27

What is another name for a chem. rxn.?

Answer 27

Chemical change

Question 28

(s)
(g)
(l)
(aq)
--^-->

Answer 28

Solid 
Gas
Liquid
Aqueous solution 
Heat

Question 29

Why do chemical equations have to be balanced?

Answer 29

Because the law of conservation of mass states that matter cannot be create or destroyed
Same # & kinds of atoms going into rxns. (In reactants) must come out of rxn. (In products)

Question 30

What is a catalyst?

Answer 30

Makes it faster & speeds up reaction but remains unchanged

Question 31

What are indicators of chemical change?

Answer 31

Bubbles (small amounts of gas formed)
Fizzing (more gas formed)
Fumes (large amount of gas formed)

Question 32

Indicators of chemical change: change in:

Answer 32

Color
Odor
Texture
Taste

Question 33

Indicators of chemical chemical change: energy a labored/released

Answer 33

Light
Heat
Electricity
Sound

Question 34

Indicators of chemical change: precipitate formed

Answer 34

May settle to the bottom of liquids
May float on top of liquids
Look like a foam material

Question 35

What are all metals?

Answer 35

Solid except for mercury which is a liquid

Question 36

What are the liquids?

Answer 36

Br2 H2O

Question 37

What are the gases?

Answer 37

H2 N2 O2 F2 Cl2

Question 38

What are the solids?

Answer 38

I2 as well as other no metals besides the diatomic molecules

Question 39

What are activity series used for?

Answer 39

To help predict whether certain chemical reactions will occur

Question 40

For metals, greater activity means

Answer 40

Greater ease of loss of electrons. This forms positive ions (cations)

Question 41

For nonmetals, greater activity means

Answer 41

Greater ease of gain of electrons. This forms negative ions (anions)

Question 42

What is the activity series usually determined by?

Answer 42

Single replacement reactions

Question 43

Where is the most active element placed in the activity series?

Answer 43

On the top & can replace any element below it to form a single replacement reaction
An element farther down in the activity series can replace any element below it but not any above it

Question 44

What are activity series based on?

Answer 44

Experiment