Bromine can be liquefied when under pressure and cooled. Liquid bromine forms a gas when warmed.
Explain what happens to the bromine molecules when liquid bromine is warmed to form a gas.
Bromine reacts with water to form a mixture of hydrobromic acid, HBr\text{HBr}HBr, and hypobromous acid, HBrO\text{HBrO}HBrO.
Write a chemical equation for this reaction.
Hydrobromic acid reacts with magnesium carbonate to form a solution containing magnesium bromide.
MgCO3(s)+2HBr(aq)→MgBr2(aq)+H2O(l)+CO2(g) \text{MgCO}_3(\text{s}) + 2\text{HBr}(\text{aq}) \rightarrow \text{MgBr}_2(\text{aq}) + \text{H}_2\text{O}(\text{l}) + \text{CO}_2(\text{g}) MgCO3(s)+2HBr(aq)→MgBr2(aq)+H2O(l)+CO2(g)Crystals of hydrated magnesium bromide, MgBr2⋅6H2O\text{MgBr}_2\cdot 6\text{H}_2\text{O}MgBr2⋅6H2O, can be obtained from this solution.
MgBr2+6H2O→MgBr2⋅6H2O \text{MgBr}_2 + 6\text{H}_2\text{O} \rightarrow \text{MgBr}_2\cdot 6\text{H}_2\text{O} MgBr2+6H2O→MgBr2⋅6H2OAn excess of hydrobromic acid is reacted with 0.125 mol0.125\text{ mol}0.125 mol of magnesium carbonate.
Show, by calculation, that the maximum theoretical mass of hydrated magnesium bromide that can be made is 36.5 g36.5\text{ g}36.5 g. [MrM_rMr of MgBr2⋅6H2O=292\text{MgBr}_2\cdot 6\text{H}_2\text{O} = 292MgBr2⋅6H2O=292]
In an experiment using 0.125 mol0.125\text{ mol}0.125 mol of magnesium carbonate, with an excess of hydrobromic acid, the mass of hydrated magnesium bromide obtained is 25.4 g25.4\text{ g}25.4 g.
Suggest two reasons why the actual mass obtained is less than the maximum theoretical mass.
