Moles

Question 1

Avogrado’s number

Answer 1

Number of particles found in one mole of a substance

Question 2

Molar mass

Answer 2

The mass of one mole of a substance, usually expressed in grams or kilograms

Question 3

Percent composition

Answer 3

The percentage by mass of each element in a compound

Question 4

Empirical formula

Answer 4

Formula that shows the ratio of elements present in the compound. Ratios are denoted by subscripts next to the element symbol

Question 5

Molecular formula

Answer 5

Expression that states the number and type of atoms present in a molecule of a substance

Question 6

step one for conversions?

Answer 6

known over 1

Question 7

how do I calculate percent composition?

Answer 7

% mass = grams of element
___________________ x 100
total grams of compound

Question 8

how do I find molar mass?

Answer 8

you look at a periodic table and look at the mass of the element ( if there is a coefficient that’s is bigger than 1 you multiply the mass times the coefficient. you do the same for the rest of the elements and add it all up. your total is your molar mass.

Question 9

how do I calculate the empirical formula?

Answer 9

1. ) pretend you have 100 gram sample of the compound (just change the % to grams)
2. ) convert the grams to moles for each element
3. ) divide each # of moles by the same smallest #
4. ) IF NEEDED, multiply the result to get whole numbers. NO DECIMALS!!

Question 10

how do I calculate molecular formula?

Answer 10

take or solve for empirical formula
solve molar mass of molecular formula and empirical formula.
divide molecular formula molar mass by empirical formula’s molar mass.

Question 11

moles road map

Answer 11

Volume 
22.4L
\_\_\_\_\_
Mole↓
    ↓
Mole
↙            ↘
Mass             representative particles
G/moles               6.02x10^23 RP
                                      Rp= atoms/molecules/formula/

Question 12

grams to grams

Answer 12

grams x moles x moles x grams
known over 1 x
1 mole of known compound over molar mass of known compound x
moles of unknown compound over moles of known compound x
mass of unknown compound over 1 mole of unkown compund

Question 13

limiting reactant

Answer 13

TWO grams to grams to grams.

Question 14

which one will be your limiting reactant?

Answer 14

smallest product

Question 15

percent yield formula

Answer 15

Actual yield
___________ x 100%
theoretical yield

Question 16

what do you have to calculate in order to get the

TY ( theoretical yield)

Answer 16

grams to gram equation for limiting reactant

Question 17

how do you calculate the excess left over in a limiting reactant reaction?

Answer 17

subtract what you get as the smallest number after limiting reactant grams to grams equation from 
known
\_\_\_\_\_
   1
that was not used.

Question 18

process in converting moles to grams

Answer 18

put known over 1
multiply
by molar mass over one
moles cross out so answer should be in grams

Question 19

process in converting moles to moles

Answer 19

MAKE SURE EQUATION IN BALANCED
known over one
multiply times
moles of unknown over moles of known

Question 20

Mole

Answer 20

Chemical mass unit 6.022 • 10^23 molecule/atoms/or other unit