Chapter 12

Question 1

Chemists use balanced chemical equations as a basis to calculate what?

Answer 1

how much reactant is needed or how much product will be formed in a reaction

Question 2

what happens when you know the quantity of one substance in a reaction?

Answer 2

you can calculate any other amount of a substance consumed or created in the reaction

Question 3

A balanced chemical equation can be interpreted in terms of what different quantities?

Answer 3

numbers of atoms, molecules or moles; mass; and

volume

Question 4

what is not changed in a chemical reaction?

Answer 4

Both the number and type of atoms

Question 5

Avogadro’s number of representative particles is equal to what?

Answer 5

one mole of a substance

Question 6

The coefficients of a balanced chemical equation indicate what?

Answer 6

the relative number of moles of reactants and products in a chemical equation

Question 7

A balanced equation obeys the law of

Answer 7

conservation of mass

Question 8

Using the mole relationship you can what?

Answer 8

relate the mass to the number of atoms in the chemical equation

Question 9

1 mole of any gas at STP occupies

Answer 9

22.4 L

Question 10

Interpret the equation in terms of numbers of representative particles
What do the Coefficients represent?

Answer 10

The number of representative particles and moles

Question 11

Mole Ratio

Answer 11

A mole ratio is a conversion factor derived from the coefficients of a balanced chemical equation interpreted in terms of moles.

Question 12

mole ratios are used to convert

between

Answer 12

a given number of moles of a reactant or product to

moles of a different product or reactant.

Question 13

When do you use a Mole To Mole Ratio?

Answer 13

You use a mole to mole ratio when you are trying to

change your compounds

Question 14

Where do you find the numbers for the mole to mole

ratio?

Answer 14

In Your Balanced Equation

Question 15

Mass to Mass Calculations

Answer 15

Substances are usually determined by mass in
grams

• From the mass of a reactant or product the
mass of any other reactant or product in a given
chemical equation can be calculated

• The mole interpretation of the equation is the
basis of this conversion

Question 16

mass to mass problem

Answer 16

1. Convert from Mass to Moles
2. Change moles of reactant to moles of product
   using the mole ratio by using the balanced
   equation
3. Change the moles of the product to the to
   grams of the product by using the molar mass
   of the product

Question 17

mass to mass problem

Answer 17

1. Convert from Mass to Moles
2. Change moles of reactant to moles of product
   using the mole ratio by using the balanced
   equation
3. Change the moles of the product to the to
   grams of the product by using the molar mass
   of the product

Question 18

what does a balanced chemical equation tell you?

Answer 18

what amounts of reactants to mix and what amounts of a product to expect

Question 19

what does quantity usually mean?

Answer 19

amount of a substance expressed in grams or moles

Question 20

stoichiometry

Answer 20

the calculation of quantities in chemical reactions is a subject of chemistry

Question 21

at the atomic level what does a balanced equation indicate?

Answer 21

the number and types of atoms that are rearranged to make the product or products.

Question 22

what is avocados’ number of representative particles equal to?

Answer 22

one mole of a substance

Question 23

since a balanced chemical equation tells you the number of representative particles what does it also tell you?

Answer 23

the number of moles

Question 24

what do the coefficients of a balanced equation indicate?

Answer 24

the relative numbers of moles of reactants and products in a chemical reaction.

Question 25

what does the law of conservation of mass indicate?

Answer 25

mass can neither be destroyed in an ordinary chemical or physical process.

Question 26

what does 1mol of any gas at stp occupy a volume

Answer 26

22.4 L

Question 27

what does the mass of the reactants equal

Answer 27

the mass of the products

Question 28

what does a balanced chemical equation allow you to determine

Answer 28

the number of moles of all other substances in the reaction

Question 29

how is the amount of a substance usually determined?

Answer 29

by measuring its mass in grams.

Question 30

what can you calculate from a mole ratio?

Answer 30

any measurement unit that is related to the mole.

Question 31

in a chemical reaction what will happen when there is an insufficient quantity of any of the reactants?

Answer 31

will limit the amount of products that form.

Question 32

limiting reagent

Answer 32

the reactant that determines the amount of product that can be formed by a reaction. occurs only until limiting reagent is used up.

Question 33

excess reagent

Answer 33

the reactant that is not completely used up in the reaction.

Question 34

when a balanced chemical equation is used to calculate the amount of product that will form during a reaction, the calculated value represents?

Answer 34

the theoretical yield

Question 35

theoretical yield

Answer 35

is the maximum amount of product that could be formed from given amounts of reactants

Question 36

actual yield

Answer 36

the amount of product that actually frms when the reaction is carried out in the laboratory

Question 37

perent yield

Answer 37

the ratio of the actual yield to the theoretical yield expressed as a percent.

Question 38

what is the percent yield a measurement of ?

Answer 38

the efficency of a reaction carried out in the laboratory