Question

Part A: Stoichiometric Amounts Reaction Run 1 Measured Mass of NaHCO3 = 1.02 g, Measured Mass of H3C6H5O7 = 0.77 g, Measured Mass of CO2 = 0.46 g. Calculate the amount (in g) of citric acid that you would need to complete the reaction for the amount of sodium bicarbonate that you used in the reaction run 1. Show all your work.

Answer 1

NaHCO3 acts as a base...

so

MW of NaHCO3 = 84.007

mol = mass/MW = 1.02/84.007 = 0.01214

MW of citric acid (triprotic) = 192.124

mol of citric acid = mass/MW = 0.77/192.124 = 0.0040

mol of CO2 = mass/MW = 0.46/44 = 0.01045

so..

Reaciton is

C6H8O7 + 3 NaHCO3 --> Na3C6H5O7 + 3 H2O + 3 CO2 (g)

so..

0.01214 mol of NaHCO3 requirse = 0.01214 /3 = 0.0040466 mol

we only have

0.0040 moles

so

citric acid required = 0.0040466 -0.0040 = 0.0000466 moles of citric acid required

mass = mol*MW = 0.0000466*192.124 = 0.008952 g of citric acid