Question

Chris the chemist works in a laboratory in which the temperature is maintained at a constant 25oc and the pressure is always 100 kpa. chris needs to analyse some calcium carbonate, caco3(s), to determine whether it is pure or has been contaminated. chris will analyse the calcium carbonate by taking a small 0.00500 mole sample and adding hydrochloric acid, hcl(aq), to it until all the calcium carbonate has disappeared and no more carbon dioxide gas, co2(g), is produced. as the gas is produced it will be collected by a water displacement method. the balanced chemical equation for this reaction is known to be: caco3(s) + 2hcl(aq) → cacl2(aq) + co2(g) + h2o(l) if the sample is pure, what volume of carbon dioxide gas will be collected?

Answer 1

The given balanced chemical equation:

$CaCO_{3}(s) +2 HCl (aq) --> CaCl_{2}(aq)+H_{2}O(l) + CO_{2}(g)$

Calculating the moles of carbon-dioxide:

Given, moles of $CaCO_{3} = 0.00500 mol CaCO_{3}$

Moles of $CO_{2} = 0.00500 mol CaCO_{3} * \frac{1 mol CO_{2}}{1 mol CaCO_{3}}$

$= 0.00500 mol CO_{2}$

Using the ideal gas equation to find out volume from moles, pressure and temperature:

PV = nRT

$P is the pressure = 100 kPa *\frac{1 atm}{101.325 kPa} = 0.987 atm$

$T is the temperature = 25^{0}C + 273 = 298 K$

$(0.987 atm)(V) = (0.00500 mol)(0.08206 \frac{L.atm}{(mol.K)}(298K)$

V = 0.124 L or 124 mL

Therefore, 124 mL of carbon dioxide will be collected.