Calculations

Question 1

Relative formula mass

Answer 1

Add up the mass number of each atom in the molecule

Question 2

Synonym for RFM

Answer 2

Relative molecular mass (RMM)

Question 3

What does the dot them H20 mean

Answer 3

The dot means to add the big number times 18 onto the rest of he equation

Question 4

Percentage by mass calculations

Answer 4

Mass of element
—————— X 100
RFM

Question 5

Empirical formula

Answer 5

The simplest ratio of atoms of each element in a compound

Question 6

Steps of empirical formula

Answer 6

1- write percentage/ mass
2- write mass number
3- divide step 1 by step 2
4- divide by the smallest

Question 7

Avogadro’ constant

Answer 7

Number of particles in a mole

= 6x10 to the power of 23

Question 8

Number of miles eq

Answer 8

Number of moles= mass/RFM

Question 9

Mass measured in

Answer 9

g, grams

Question 10

Moles measured in

Answer 10

mol

Question 11

RFM measured in

Answer 11

g mol-1

Question 12

Reacting mass calculations

Answer 12

1- write balanced eq
2- calc number of moles from the data given in the question
3- use the equation to work out the number of miles or the desired compound (this could be product or starting material)
4- calculate mass of desired compound