1e - chemical formulae, equations, calculations

Question 1

how to calculate relative formula mass (using atomic mass)

Answer 1

the sum of the atomic masses shown in the equation

Question 2

what is a mole?

Answer 2

the unit for the amount of a substance

Question 3

how to calculate moles

Answer 3

mass/relative formula mass

Question 4

how to calculate mass

Answer 4

moles x relative formula mass

Question 5

how to calculate relative formula mass (using moles)

Answer 5

mass/moles

Question 6

how to calculate percentage yield

Answer 6

(actual yield/theoretical yield) x 100

Question 7

what is the empirical formula?

Answer 7

the simplest whole-number ratio of atoms in a compound

Question 8

what is the molecular formula?

Answer 8

the number of each type of atom in a molecule

Question 9

how do you calculate empirical formula?

Answer 9

1. Calculate the number of moles of each element
2. Divide all results by the smallest number of moles found in Step 1
3. Use the lowest whole-number ratio of the moles as subscripts

Question 10

how do you calculate molecular formula?

Answer 10

1. Calculate the molar mass of the empirical formula
2. Divide the given molecular molar mass by the molar mass calculated for the empirical formula
3. Multiply each subscript by the whole number that resulted from step 2