30 liters of NH3, containing 40% impurities, reacts with H2SO4. Find the mass of the formed

| April 13, 2021 | education

30 liters of NH3, containing 40% impurities, reacts with H2SO4. Find the mass of the formed ammonium sulfate salt (NH4) 2SO4.

Given:
V mixture (NH3) = 30 l
φ approx. = 40%

To find:
m ((NH4) 2SO4) -?

Decision:

The solution to such a task involves the implementation of such basic points as:

drawing up the equation of a chemical reaction according to the condition of the problem and the correct arrangement of the coefficients in front of the substances;
calculation of the molar masses of substances that are used in the problem, using the periodic system of D. I. Mendeleev;
checking the units of measurement provided in the condition for compliance with the SI system; if there is a discrepancy, translate them;
understanding of the terms “amount of substance”, “volume fraction”;
making calculations using the necessary formulas.
Taking actions based on known data
1) Using the periodic system of D.I.Mendeleev, calculate the molar masses of substances, which will be numerically equal to the molecular weights. However, of the substances specified in the condition of the problem, only ammonium sulfate is needed for operation:
Mr ((NH4) 2SO4) = Ar (N) * 2 + Ar (H) * 4 * 2 + Ar (S) + Ar (O) * 4 = 14 * 2 + 1 * 8 + 32 + 16 * 4 = 132 g / mol;

2) Make up the equation of the ongoing chemical reaction:
2NH3 + H2SO4 => (NH4) 2SO4;

3) Determine the volume fraction of pure NH3 in the mixture:
φ (NH3) = 100% – φ approx. = 100% – 40% = 60%;

4) Find the volume of pure NH3:
V (NH3) = φ (NH3) * V mixture (NH3) / 100% = 60% * 30/100% = 18 l;

5) Calculate the amount of NH3 substance:
n (NH3) = V (NH3) / Vm = 18 / 22.4 = 0.8 mol;

Calculations to find the answer to the question of the problem
6) Determine the amount of substance (NH4) 2SO4 (taking into account the reaction equation):
n ((NH4) 2SO4) = n (NH3) / 2 = 0.8 / 2 = 0.4 mol;

7) Calculate the mass of (NH4) 2SO4:
m ((NH4) 2SO4) = n ((NH4) 2SO4) * Mr ((NH4) 2SO4) = 0.4 * 132 = 53 g.

Answer: The mass of (NH4) 2SO4 is 53 g.



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