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CGB IGCSE Chemistry
Practice Problems - the mole 2
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Practice Problems

The Mole 2

 

  1. When carbon burns in oxygen, carbon dioxide is formed.

C(s) + O2(g) CO2(g)

    1. Calculate the mass of 1 mole of carbon.
    2. Calculate the mass of 1 mole of oxygen.
    3. Calculate the mass of 1 mole of carbon dioxide.
    4. If 3.4 moles of carbon is burned in excess oxygen, how many moles of carbon dioxide are formed.
    5. Find out how much carbon dioxide is formed if 24 g of carbon is burned in excess oxygen.
    6. Find out how many grams of carbon need to be burned to form 35.2 grams of carbon dioxide.
    7. How many moles of carbon and oxygen need to react to form 13 moles of carbon dioxide.

 

  1. Hydrogen burns in oxygen to form water.

2H2(g) + O2(g) 2H2O(l)

    1. Calculate the mass of 1 mole of hydrogen.
    2. Calculate the mass of 1 mole of water.
    3. How many moles of hydrogen and oxygen need to be burned to form 6 moles of water?
    4. Find out how much water is formed if 5 moles of hydrogen is burned in excess oxygen.
    5. Find out how many grams of water is formed if 28 g of hydrogen is burned in excess oxygen.

 

  1. When aqueous solutions of sodium chloride and silver nitrate are mixed, a white precipitate of silver chloride forms.

AgNO3(aq) + NaCl(aq) AgCl(s) + NaNO3(aq)

    1. Calculate the mass of 1 mole of silver nitrate.
    2. Calculate the mass of 1 mole of sodium chloride.
    3. Calculate the mass of 1 mole of silver chloride.
    4. Calculate the mass of 1 mole of sodium nitrate.
    5. How many moles of silver nitrate and sodium chloride have to react to form 7.5 moles of silver chloride?
    6. If 11.7 grams of sodium chloride are added to excess silver nitrate how many grams of silver chloride are formed?
    7. If 255 grams of silver nitrate are added to excess sodium chloride how many grams of silver chloride are formed?

 

  1. Molten lithium chloride is decomposed to form lithium and chlorine in electrolysis.

2LiCl(l) 2Li(l) + Cl2(g)

    1. How many moles of lithium chloride need to be decomposed to form 18 moles of chlorine gas?
    2. How many moles of lithium and chlorine are formed if 25 moles of lithium chloride are decomposed?
    3. If 119 g of lithium chloride are decomposed, how many grams of lithium and chlorine are formed?

 

  1. When hydrogen is passed over heated copper(II)oxide, copper(II)oxide is reduced to copper and hydrogen is oxidised to water.

CuO(s) + H2(g) Cu(s) + H2O(l)

    1. Calculate the mass of 1 mole of copper(II)oxide.
    2. Calculate the mass of 1 mole of hydrogen.
    3. If 344 g of copper(II)oxide react with 10 g of hydrogen, which substance is in excess?
    4. If 344 g of copper(II)oxide react with 10 g of hydrogen, name the substances present when the reaction is complete and find the mass of each.
    5. If 208 g of copper(II)oxide react with 4 g of hydrogen, which substance is in excess?
    6. If 208 g of copper(II)oxide react with 4 g of hydrogen, name the substances present when the reaction is complete and find the mass of each.