1. What mass of magnesium oxide is produced when 60 g of magnesium is burned in air?

    

 

2. Analysis of a gaseous oxide of sulfur shows that it contains 60% oxygen by mass.( Ar             values : S= 32, O=16)

a) What is the percentage mass of sulfur in the oxide

 

 

b) Work out the formula of the oxide.

 

 

3. Heating a test tube containing 2g of calcium carbonate produced 1.08g of calcium oxide when it was reweighed. The equation for the reaction is:

 

                         CaCO3(s) ---> CaO(s) + CP2(g)

                       (Mr values: CaCO3= 100, CaO= 56)

 

a) Calculate the amount of calcium oxide you would expect to be formed from 2g of calcium carbonate.

 

 

b) Compare the value to the mass obtained in the experiment. Suggest a reason for the difference.

 

 

4. Ammonium nitrate (NH4NO3) is an ionic subtance.

    Relative atomic masses: H=1, N=14, O= 16.

    Calculate the percentage mass of nitrogen in ammonium nitrate. Show clearly how you work     out your answer.

 

 

 

5. The balanced equation below shows what happens when a strip of magnesium metal is dissolved in a solution of hydrochloric acid.

 

                          Mg (s) + 2HCl (aq) ---> MgCl2 (aq) + H2(g)

Mathew dissolved a piuce of magnesium in an excess of hydrochloric acid. He made 7.5g of MgCl2. What mass of magnesium did he start with? Show your full working.

 

 

 

6. Potasium nitrate is a fertiliser. It can be produced by neutralising nitric acid (HNO3) with potassium hydroxide (KOH). 

The chemical formula of potassium nitrate is KNO3. Calculate the percentage mass of potassium in potassium nitrate. Show all your workings.

 

 

7. What mass of sodium is needed to produce 108.2g of sodium oxide (Na2O)?

    

 

8. a) Calculate the percentage mass of carbon in:

       i) CaCO3         ii)CO2      iii)CH4

        

 

   b) Calculate the percentage mass of metal in:

       i)Na2O            ii)Fe2O3        iii)Al2O3