Question

How many liters of 0.500 M calcium hydroxide would be needed in Reaction 3 to capture all the carbon dioxide gas produced from 1.00L acetic acid in Reaction 2?

Assume STP conditions

Reaction 2: HC2H3O2 +O2 = 2CO2+ 2H2

Reaction 3: CO2 +Ca(OH)2 = CaCO3 + H2O

Answer 1

from balaned equation :  

1.00 L acetic acid gives 2.00 L of CO2

this total CO2 captured by Ca(OH)2

volume of CO2 = 2 L

pressure at STP = 1 atm

Temperature = 273 K

P V = n R T

n = P V / R T

      = 1 x 2 / 0.08121 x 273

       = 0.0892

moles of CO2 = 0.0892

from balanced equation 3) moles of CO2 = moles of Ca(OH)2

moles of Ca(OH)2 = 0.0892

molarity of Ca(OH)2 = 0.500 M

molarity = moles / volume

volume = moles / molarity

           = 0.0892 / 0.500

           = 0.178 L

          = 178 mL

volume of Ca(OH)2 = 178 mL