What volume of CO2 is formed when 40 grams of limestone containing 8% impurities 70

| April 4, 2021 | education

What volume of CO2 is formed when 40 grams of limestone containing 8% impurities 70 grams of 15% hydrochloric acid solution acts on it? The practical gas yield is 80% of the theoretical.

Given: m izv. (CaCO3) = 40 g ω approx. = 8% m p-pa (HCl) = 70 g ω (HCl) = 15% ω out. = 80%
Find: V pr. (CO2) -?
Decision:
1) Write the reaction equation: CaCO3 + 2HCl => CaCl2 + H2O + CO2 ↑ 2) Find the mass fraction of pure CaCO3 in limestone: ω (CaCO3) = 100% – ω approx. = 100% – 8% = 92%; 3) Find the mass of the substance CaCO3: m (CaCO3) = ω (CaCO3) * m izv. / 100% = 92% * 40/100% = 36.8 g; 4) Find the amount of CaCO3: n (CaCO3) = m (CaCO3) / Mr (CaCO3) = 36.8 / 100 = 0.37 mol; 5) Find the mass of the substance HCl: m (HCl) = ω (HCl) * m solution (HCl) / 100% = 15% * 70/100 = 10.5 g; 6) Find the amount of the substance HCl: n (HCl) = m (HCl) / Mr (HCl) = 10.5 / 36.5 = 0.29 mol; 7) Compare the amount of CaCO3 and HCl: HCl is in short supply, therefore, calculations will be carried out for it; 8) Find the amount of substance CO2 (taking into account the reaction equation): n (CO2) = n (HCl) / 2 = 0.29 / 2 = 0.15 mol; 9) Find the theoretical volume of CO2: V theor. (CO2) = n (CO2) * Vm = 0.15 * 22.4 = 3.36 l; 10) Find the practical volume of CO2: V pr. (CO2) = V theor. (CO2) * ω out. / 100% = 3.36 * 80% / 100% = 2.68 liters.
Answer: The volume of CO2 gas generated was 2.68 liters.



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