1. Lithium hydrogen carbonate decomposes by heat; the reaction is represented by
ID: 837988 • Letter: 1
Question
1. Lithium hydrogen carbonate decomposes by heat; the reaction is represented by the balanced equation:
2LiHCO3 (s) --------> Li2CO3(s) + CO2(g) + H20 (g)
a.) If 0.24 mol of LiHCO3 is decomposed completely, how many mol of Li2CO3 will be formed?
b.) If 136 g of LiHCO3 are decomposed completely, how many g of Li2CO3 will be formed?
c.) What is the combined weight of the CO2 and H20 in b?
2. a.) A sample of LiHCO3 and sand mixture weighing 9.62 g is decomposed by heat. After cooling, the residue, which is composed of Li2CO3 and sand, is formed to weigh 6.85 g. Assuming that the sand in the sample is unaffected, calculate the weight loss due to the evolution of gaseous CO2 and H2O.
b.) Calculate the weight of LiHC03 in the original mixture.
Explanation / Answer
1. Lithium hydrogen carbonate decomposes by heat; the reaction is represented by the balanced equation:
a.) If 0.24 mol of LiHCO3 is decomposed completely, how many mol of Li2CO3 will be formed?
2mole(LiHCO3 (s))--->1mole( Li2CO3(s)) + 1mole(CO2(g))+1mole(H20 (g)) or
1mole(LiHCO3 (s))--->0.5mole( Li2CO3(s)) + 0.5mole(CO2(g))+0.5mole(H20 (g))
b.) If 136 g of LiHCO3 are decomposed completely, how many g of Li2CO3 will be formed?
2LiHCO3 (s)----> Li2CO3(s) + CO2(g) + H20 (g)
135.88g ---> 73.88g + 44g + 18g
c.) What is the combined weight of the CO2 and H20 in b?
combined weight of CO2 and H2O in part b=44g(CO2) + 18g(H2O)=62g
2. a.) A sample of LiHCO3 and sand mixture weighing 9.62 g is decomposed by heat. After cooling, the residue, which is composed of Li2CO3 and sand, is formed to weigh 6.85 g. Assuming that the sand in the sample is unaffected, calculate the weight loss due to the evolution of gaseous CO2 and H2O.
Total mass=mass of sand + LiHCO3=9.62g
Mass of Li2CO3+sand=6.85g
weght loss by gases(since weght of sand is unaffected)=9.62-6.85=2.77g
b.) Calculate the weight of LiHC03 in the original mixture.
using information in part b)
62gram of gasses are produced from LiHCO3=135.88g
2.77gram of gasses are produced from LiHCO3=135.88/62*2.77=6.071g
Hence weight of LiHCO3=6.071g (out of 9.62g mixture)
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.