What volume of gas is evolved at S.t.p if 2g of calcium trioxocarbonate (IV) is added to a solution of hydrochloric acid? [Ca = 40, C = 12, O = 16, Cl = 35.5, H = 1 Molar volume of agas at s.t.p = 22.4 dm3
A. 112 cm2 B. 224 cm2 C. 448 cm2 D. 2240 cm2
Correct Answer: C
Explanation
CaCO3(s) + 2HCl[sub](aq) → CaCl2 + H2O(l) + CO2 The relative molecular mass of CaCO3 = 40 + 12 + 16 * 3 = 52 +48 = 100 ; Relative molecular mass of CO2 = 12 + 10 * 2 = 44 From the above equation, 100g of CaCO3reacts with 44g of CO2 at s.t.p. i.e 22.4 dm3 2g of CaCO3 will react with (2*22.4)/100 of CO2 = 0.448 dm3 0.448 dm3 = 0.448 * 1000 = 448cm3[/sub]
