A 1.205 g sample mixture of lithium hydrogen carbonate is decomposed by heating. If they mass loss is 0.275g, what is the percentage of LiHCO3 in the unknown mixture?

To determine the percent of LiHCO3 in the mixture, we need to calculate for the amount of LiHCO3 by first knowing what really happens in the process. We do as follows:

2 LiHCO3 (s) - - Heat - - > Li2CO3 (s) + H2CO3 (g)

0.275 g = mass of H2CO3

mass of LiHCO3 = 0.275g (1 mol / 62.03 g) (2 mol LiHCO3 / 1 mol H2CO3) (67.96 g / 1 mol) = 0.6026 g LiHCO3

% percent = 0.6026 / 1.205 x 100 = 50%