Quantiative Chemistry

Question 1

What is relative atomic mass (ram) ?

Answer 1

The mass of the atom compared to that of a carbon- 12 atom, which has a mass of 12

Question 2

What is relative formula mass?

Answer 2

Found by adding together all the atomic masses of all the atom in the formula of the element or compound

Question 3

What is the equation to find the percentage of an element in a compound?

Answer 3

mass of element in one mole of the compound
—————————————————————— x 100
Mass of one mole of the compound

Question 4

What is a mole?

Answer 4

• An amount of a chemical
• RFM of a substance in grams is known as one mole of that substance

Question 5

What is the equation to find a mole?

Answer 5

Moles = mass/rfm

Question 6

What is the equation find to mass?

Answer 6

Mass= moles X RFM

Question 7

What are the steps to calculate reacting masses?

Answer 7

① make sure you have a balanced equation
② write the info you know from the question
③ workout the RFM of reactants and products

Question 8

Limiting reactants

Answer 8

• Reactant that’s all used up = limiting reactant/ reagant

• Reactant that’s left over = in excess

Question 9

What is the equation for percentage yield?

Answer 9

Actual yield / theoretical yield x100

Question 10

Reasons yield may be less than 100%

Answer 10

• Loss of product in separation from reaction mixture
• Due to side reactions
• reaction is reversable and doesn’t go to completion