Quantitative Chemistry - Unit 1 Topic 7

Question 1

What is RAM?

Answer 1

Relative atomic mas

Mass of the atom compared to the carbon 12 isotope which has a mass of exactly 12.

Question 2

What is RFM/RMM?

Answer 2

Relative Formula Mass/Relative Molecular Mass

Sum of all atomic masses in compound.

Question 3

What is a mole?

Answer 3

Amount of a chemical

Question 4

Mass of 1 mol of MgO

Answer 4

24 + 16

40g

Question 5

% of nitrogen in 1 mol of ammonia?

Answer 5

% = 14/17 x 100

82.4%

Question 6

How many moles in 2.8kg of nitrogen? (N2)

Answer 6

2 x 14 = 28

2800/28

=100 mol

Question 7

What is the mass of 3 moles of NH3?

Answer 7

14 + (3x1) = 17

3 x 17 = 51g

Question 8

How much CaO do you get from 800g of CaCO3?

Answer 8

CaO CaCO3

m= 280g m= 500g

n= 5 moles n= 5 moles

RFM= 56 RFM= 100

Question 9

5.6g of sulphur reacted with sulfur to form 7.5g of iron sulfide. Calculate the percentage yield. (FeS)

Answer 9

Fe FeS

m= 5.6g m= 8.8g

n= 0.1 mol n= 0.1 mol

RFM= 56 RFM= 88

% = 7.5/8.8 x 100 = 85%