The dissolution of all taken zinc took 129.2 ml of a solution of 20% hydrochloric

| May 17, 2021 | education

The dissolution of all taken zinc took 129.2 ml of a solution of 20% hydrochloric acid with a density of 1.11 g / ml. Determine the mass of zinc taken for the reaction and the volume of released hydrogen.

Given: V solution (HCl) = 129.2 ml ω (HCl) = 20% ρ solution (HCl) = 1.11 g / ml
Find: m (Zn) -? V (H2) -?
Decision:
1) Write the reaction equation: Zn + 2HCl => ZnCl2 + H2 ↑ 2) Find the mass of the HCl solution: m solution (HCl) = ρ solution (HCl) * V solution (HCl) = 1.11 * 129.2 = 143.412 g; 3) Find the mass of the substance HCl: m (HCl) = ω (HCl) * m solution (HCl) / 100% = 20% * 143.412 / 100% = 28.682 g; 4) Find the amount of the substance HCl: n (HCl) = m (HCl) / Mr (HCl) = 28.682 / 36.5 = 0.786 mol; 5) Find the amount of substance Zn (taking into account the reaction equation): n (Zn) = n (HCl) / 2 = 0.786 / 2 = 0.393 mol; 6) Find the mass of the substance Zn: m (Zn) = n (Zn) * Mr (Zn) = 0.393 * 65 = 25.55 g; 7) Find the amount of substance H2 (taking into account the reaction equation): n (H2) = n (HCl) / 2 = 0.786 / 2 = 0.393 mol; 8) Find the volume of gas H2: V (H2) = n (H2) * Vm = 0.393 * 22.4 = 8.8 liters.
Answer: The mass of Zn is 25.55 g; the volume of H2 gas is 8.8 liters.



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