Year 11 Chemistry – Mole Calculations

1. Find the molar mass of the following:

a) oxygen O2 b) carbon dioxide CO2 c) sulfuric acid H2SO4

d) ammonia NH3 e) ethanoic acid CH3COOH f) palmitic acid CH3(CH2)14COOH

2. Calculate the number of moles of each of the following particles, given the total number;

a) 9 x 1026 hydrogen chloride molecules b) 1.5 x 1024 protons

c) 6 x 1022 ammonia molecules d) 1.2 x 1025 grains of sand

3. If we have 6 x 1027 molecules of carbon dioxide:

a)  how many carbon atoms are present?

b)  How many moles of carbon atoms are present?

c)  How many oxygen atoms are present?

d)  How many moles of oxygen atoms are present?

4. If we have 9 x 1026 molecules of ethanoic acid, CH3COOH, how many moles of each of the following are present?

a) CH3COOH molecules b) C atoms

c) O atoms d) atoms altogether

5. If we have 5 mol of ammonia molecules, NH3:

a)  How many molecules are present?

b)  How many moles of nitrogen atoms are present?

c)  How many hydrogen atoms are present?

d)  How many atoms are present altogether

6. How many moles of oxygen atoms are in each of the following:

a)  1 mol oxygen molecules, O2

b)  2 mol potassium permanganate solution, KmnO4

c)  0.5 mol butanoic acid, CH3CH2CH2COOH

d)  12 mol iron (III) hydroxide, Fe(OH)3

7. How many moles of each of the following substances are present?

a)  methane molecules, CH4, in 25.0 g of methane

b)  water in 1.00 kg (1L)

c)  molecules in the insecticide bromoethane, CH3Br, in 100g bromoethane

d)  oxygen atoms in 452 g of ozone, O3

e)  hydrogen atoms in 196 g sulfuric acid, H2SO4

8. What mass would I need to measure out the following:

a)  5.0 mol of sulfur dioxide gas, SO2

b)  0.10 mol of sodium hydroxide, NaOH

c)  1.2 x 1025 molecules of ethanoic acid, CH3COOH

d)  7.5 x 1022 atoms of neon

9. Find the molar concentrations (molarity) of each of the following solutions with respect to the substance named:

a)  5 mol zinc chloride, ZnCl2, dissolved in 2.5 L of solution

b)  0.010 mol of sodium carbonate, Na2CO3, dissolved in 180 ml of solution

c)  10.0 g of sodium chloride, NaCl, dissolved in 250 ml of solution

d)  2.00 kg sucrose, C12H22O11, dissolved in 4.0 L of sugar syrup solution

10. Calculate the number of moles of hydrogen chloride that would have been used to prepare the following solutions:

a)  1.50 L of 0.10 mol/L solution

b)  300 ml of 0.55 M solution