1
Extension Calculations for F321
In this worksheet assume that one mole of any gas occupies 24.0 dm3 at room temperature and pressure (r.t.p.)
1 Calculate the volume of oxygen, at room temperature and pressure, needed to fully combust 2.4 dm3 of butane, C4H10.
C4H10(g) + O2(g) à 4CO2(g) + 5H2O(l)
15.6 dm3
2 What is the volume of carbon dioxide, measured at r.t.p, produced when 240 dm3 of pentane is completely combusted?
C5H12 + 8O2 à 5CO2 + 6H2O
1200 dm3
3 Hydrogen, H2, reacts with nitrogen, N2, to form the gas ammonia, NH3.
(a) Write down the balanced equation for this reaction making sure to include the state symbol for each substance.
N2(g) + 3H2(g) → 2NH3(g)
(b) Calculate the volume of hydrogen needed to make 1200000 dm3 of ammonia. All gas volumes measured at r.t.p.
1800000 dm3
4 Ethane, C2H6, reacts with excess chlorine, Cl2, to give hexachloroethane, C2Cl6, according to the equation below.
C2H6(g) + 6Cl2(g) à C2Cl6(g) + 6HCl(g)
(a) Calculate the mass of hexachloroethane that can be produced from 3.246 g of ethane.
25.64 g
(b) Calculate the volume of chlorine, at r.t.p., needed to make 2.978 g of hexachloroethane
1.809 dm3
5 Sulfur burns in air as shown by the equation.
S(s) + O2(g) à SO2(g)
Calculate the volume of sulfur dioxide measured at r.t.p. that can be made from;
(a) burning 24.0 g of sulfur in oxygen;
17.9 dm3
(b) burning sulfur in 2.4 dm3 of pure oxygen at r.t.p.
2.4 dm3
6 Aqueous ammonium nitrite(III), NH4NO2(aq) decomposes when it is heated according to the equation shown.
NH4NO2(aq) à N2(g) + 2H2O(l)
50.0 cm3 of a 0.120 mol dm-3 ammonium nitrite(III) solution was completely decomposed.
(a) Calculate the number of moles of ammonium nitrite in the solution before it was decomposed.
0.006 moles
(b) Hence calculate the number of moles of nitrogen that is produced.
0.006 moles
(c) Hence calculate the volume of nitrogen produced at r.t.p.
144 cm3
7 Nitric oxide reacts with oxygen in the air to make nitrogen dioxide.
2NO(g) + O2(g) à 2NO2(g)
(a) Calculate the volume of oxygen, measured at r.t.p, needed to react completely with 12.0 cm3 of nitric oxide, NO.
6.00 cm3
(b) Calculate the volume of air needed to react completely with 12.0 cm3 of nitric oxide, NO.
Assume that air contains 20% by volume oxygen.
30 cm3
8 Chloe heats a sample of 7.48 g of potassium chlorate(V). It makes oxygen and potassium chloride.
2KClO3(s) à 2KCl(s) + 3O2(g)
(a) What is the mass of oxygen formed?
Mr KClO3 = 122.6
Mass O2 = 2.93 g
(b) What is the volume of oxygen collected at r.t.p?
2200 cm3 (3 s.f.)