Question
Chemistry Question on Some basic concepts of chemistry
Volume of CO2 obtained by the complete decomposition of 9.85 gm BaCO3 is:
2.24 lit.
1.12 lit.
0.84 lit.
0.56 lit.
1.12 lit.
Solution
Molar mass of Ba = 137.33 g/mol
Molar mass of C = 12.01 g/mol
Molar mass of O = 16.00 g/mol
Molar mass of BaCO3 = 137.33 + 12.01 + 3 x 16.00 = 197.34 g/mol
Moles of BaCO3 = Molar massMass
Moles of BaCO3 = 197.34 g/mol9.85 g ≈ 0.05 moles
Balanced chemical equation for the decomposition of BaCO3
BaCO3→BaO+CO2
The stoichiometry tells us that one mole of BaCO3 produces one mole of CO2.
Moles of CO2 = Moles of BaCO3 ≈ 0.05 moles
Now, use the ideal gas law to find the volume of CO2 at standard temperature and pressure (STP):
The molar volume of an ideal gas at STP is 22.4 liters/mol.
Volume of CO2 = Moles of CO2 x Molar volume at STP
Volume of CO2 = 0.05 moles x 22.4 liters/mole = 1.12 liters
So, the correct option is (B): 1.12 lit.