Question

He shell of a chicken’s egg makes up 5% of the mass of an average egg. An average egg has a

Answer 1

First of all, you have to write a balance equation for the reaction. The balanced equation for the reaction is:
CaCO3 + 2CH3COOH = [CH3COO]2Ca +CO2 + H20
Next, find the mass of the shell.
For an average egg, the mass is 0.05 * 50 = 2.5 g. 
To convert this mass to moles, we have: 2.5/100 = 0.025 Moles. This is the mole of calcium carbonate.
To calculate the mole of ethanolic acid, we have: 50 * 0.001 * 2 = 0.1. This value is for 2 molecules, therefore for one molecule, we have: 0.1/2 = 0.05. 
From the equation of reaction, one mole of calcium carbonate is required to neutralize two moles of ethanolic acid.
Thus, 0.05/0.025 = 2. This imply that two complete egg shells will be needed to neutralize 50cm of ethanolic acid.