Ch 9 Section 2

Question 1

the balanced chemical equation is the key step in all stoichiometric calculations because the mole ratio is

Answer 1

obtained directly from it

Question 2

solving any reaction stoichiometry problem must begin with a

Answer 2

balanced equation

Question 3

chemical equations help us plan the amounts of reactants to use in a chemical reaction without having to

Answer 3

run the reactions in the laboratory

Question 4

theoretical stoichiometry calculations tell us the amounts of reactants and products for a given chemical reaction under

Answer 4

ideal conditions, in which reactants are completely converted into products

Question 5

many reactions do not proceed such that all reactants are completely converted into

Answer 5

products

Question 6

theoretical stoichiometric calculations allow us to determine the maximum amount of product that could be obtained in a reaction when the reactants are not

Answer 6

pure or byproducts are formed in addition to the expected products

Question 7

the plan for a simple mole conversion problem requires one conversion factor– the stoichiometric mole ratio of the unknown substance to the

Answer 7

given substance from the balanced equation

Question 8

to solve this type of problem (mole to mole) simply multiply the

Answer 8

known quantity by the appropriate conversion factor

Question 9

given quantity x conversion factor =

Answer 9

unknown quantity

Question 10

amount of given substance (mol) x mol unknown/ mol given →

Answer 10

amount of unknown substance (mol)

Question 11

the plan for mole-to-gram conversions requires two conversion factors– the mole ratio for the unknown substance to the given substance and the molar mass of the

Answer 11

unknown substance for the mass conversion.

Question 12

amount of given mol unknown/ Mmof unknown g/
substance x mol given x 1 mol unknown
=

Answer 12

mass of unknown substance

g

Question 13

the plan to calculate the amount in moles from a given mass of another substance requires two additional pieces of data:

Answer 13

molar mass of the given substance and the mole ratio

Question 14

because the known quantity is a mass, the conversion factor will need to be 1 mol divided by

Answer 14

molar mass

Question 15

mass of given substance (g) x 1 mol given/ Mm of given (g) x mol unknown/ mol given -

Answer 15

amount of unknown substance (mol)

Question 16

mass of given substance (g) x 1 mol given/ Mm of given (g) x mol unknown/ mol given x Mm of unknown (g)/ 1 mol unknown =

Answer 16

mass of unknown substance (g)

Question 17

mass-mass calculations are more practical than other

Answer 17

mole calculations

Question 18

you can never measure moles

Answer 18

directly

Question 19

you are generally required to calculate the amount in moles of a substance from its

Answer 19

mass, which you can measure in the lab

Question 20

3 additional pieces of data are needed to solve mass-mass problems:

Answer 20

molar mass of the given substance, the mole ratio, and the molar mass of the unknown substance