Answer:
a) 101%
b)59.7%
Explanation:
The equation for the thermal decomposition of baking soda is shown;
2NaHCO3 → Na2CO3 + H2O + CO2
Number of moles of baking soda= mass/molar mass= 1.555g/84.007 g/mol = 0.0185 moles
From the reaction equation;
2 moles of baking soda yields 1 mole of sodium carbonate
0.0185 moles of baking soda will yield = 0.0185 moles ×1 /2 = 9.25 ×10^-3 moles of sodium carbonate.
Therefore, mass of sodium carbonate= 9.25 ×10^-3 moles × 106gmol-1= 0.9805 g of sodium carbonate. This is the theoretical yield of sodium carbonate.
%yield = actual yield/theoretical yield ×100
% yield = 0.991/0.9805 ×100
%yield = 101%
Since ;
2NaHCO3 → Na2CO3 + H2O + CO2
And H2O + CO2 ---> H2CO3
Hence I can write, 2NaHCO3 → Na2CO3 + H2CO3
Molar mass of H2CO3= 62.03 gmol-1
Molar mass of baking soda= 84 gmol-1
Therefore, mass of baking soda=
0.325/62.03 × 2 × 84 = 0.88 g of NaHCO3
% of NaHCO3= 0.88/1.473 × 100 = 59.7%
