Sodium chlorate (NaClO3\text{NaClO}_3NaClO3) is a compound that decomposes when heated to produce sodium chloride and oxygen gas. The chemical equation for this thermal decomposition is:
2NaClO3(s)→2NaCl(s)+3O2(g) 2\text{NaClO}_3(\text{s}) \rightarrow 2\text{NaCl}(\text{s}) + 3\text{O}_2(\text{g}) 2NaClO3(s)→2NaCl(s)+3O2(g)Sodium chlorate is used in emergency chemical oxygen generators (commonly called "oxygen candles") on commercial aircraft to rapidly produce breathable oxygen gas.
A passenger cabin emergency mask system requires a total oxygen volume of 108 dm3108\text{ dm}^3108 dm3. Calculate the amount of oxygen, in moles, required. (Assume that the volume of one mole of oxygen gas under these conditions is 24 dm324\text{ dm}^324 dm3.)
Use your answer to (a)(i) to calculate the mass, in grams, of sodium chlorate required to produce 108 dm3108\text{ dm}^3108 dm3 of oxygen. [Relative atomic masses: Na=23\text{Na} = 23Na=23, Cl=35.5\text{Cl} = 35.5Cl=35.5, O=16\text{O} = 16O=16]
The oxygen generator also contains iron powder (Fe\text{Fe}Fe). This reacts with a small portion of the oxygen formed during the process according to the following equation:
4Fe(s)+3O2(g)→2Fe2O3(s) 4\text{Fe}(\text{s}) + 3\text{O}_2(\text{g}) \rightarrow 2\text{Fe}_2\text{O}_3(\text{s}) 4Fe(s)+3O2(g)→2Fe2O3(s)Suggest one reason why the designers of the oxygen generator want this reaction to occur.
The generator also contains solid barium peroxide (BaO2\text{BaO}_2BaO2) which reacts with toxic trace chlorine gas (Cl2\text{Cl}_2Cl2) produced in minor side-reactions to form solid barium chloride (BaCl2\text{BaCl}_2BaCl2) and oxygen gas (O2\text{O}_2O2). Construct a balanced chemical equation for this reaction. Include state symbols.
To confirm the presence of chloride ions in the post-reaction residue, a sample is dissolved in water and reacted with silver nitrate solution (AgNO3\text{AgNO}_3AgNO3):
AgNO3(aq)+NaCl(aq)→AgCl(s)+NaNO3(aq) \text{AgNO}_3(\text{aq}) + \text{NaCl}(\text{aq}) \rightarrow \text{AgCl}(\text{s}) + \text{NaNO}_3(\text{aq}) AgNO3(aq)+NaCl(aq)→AgCl(s)+NaNO3(aq)What name is given to this type of reaction?
What method would you use to separate the solid silver chloride from the final reaction mixture?
80 exam-style questions on Edexcel IGCSE Chemistry Chemical formulae, equations and calculations. Each one has a worked solution and a mark scheme showing where the marks go.