Question

Срочно даю 50 балов К раствору сульфатной кислоты массой 100г с массовой долей растворенного вещества 23% добавили алюминий . Найдите объём газа который при этом выделился

Answer 1

Calculation of the Volume of Gas Evolved

To calculate the volume of gas evolved when aluminum is added to a solution of sulfuric acid, we need to consider the balanced chemical equation for the reaction between aluminum and sulfuric acid. The balanced equation is as follows:

2Al + 3H2SO4 → Al2(SO4)3 + 3H2↑

From the balanced equation, we can see that for every 2 moles of aluminum, 3 moles of hydrogen gas are produced. Therefore, the stoichiometric ratio between aluminum and hydrogen gas is 2:3.

Given that the mass of the sulfuric acid solution is 100 g and the mass fraction of the dissolved substance (sulfuric acid) is 23%, we can calculate the mass of sulfuric acid in the solution:

Mass of sulfuric acid = Mass of solution × Mass fraction of sulfuric acid = 100 g × 0.23 = 23 g

Next, we need to determine the number of moles of sulfuric acid in the solution. To do this, we divide the mass of sulfuric acid by its molar mass. The molar mass of sulfuric acid (H2SO4) is 98.09 g/mol.

Number of moles of sulfuric acid = Mass of sulfuric acid / Molar mass of sulfuric acid = 23 g / 98.09 g/mol ≈ 0.234 mol

Since the stoichiometric ratio between aluminum and hydrogen gas is 2:3, we can calculate the number of moles of hydrogen gas produced by multiplying the number of moles of sulfuric acid by the stoichiometric ratio:

Number of moles of hydrogen gas = Number of moles of sulfuric acid × (3 moles of H2 / 2 moles of Al) = 0.234 mol × (3/2) ≈ 0.351 mol

Finally, we can use the ideal gas law to calculate the volume of gas at standard temperature and pressure (STP). STP is defined as a temperature of 0 degrees Celsius (273.15 Kelvin) and a pressure of 1 atmosphere (101.325 kilopascals).

The ideal gas law equation is:

PV = nRT

Where: P = Pressure (in atmospheres) V = Volume (in liters) n = Number of moles R = Ideal gas constant (0.0821 L·atm/(mol·K)) T = Temperature (in Kelvin)

At STP, the pressure is 1 atmosphere and the temperature is 273.15 Kelvin. Plugging in these values, along with the number of moles of hydrogen gas, we can solve for the volume:

V = (nRT) / P = (0.351 mol × 0.0821 L·atm/(mol·K) × 273.15 K) / 1 atm ≈ 8.97 L

Therefore, the volume of gas that is evolved when aluminum is added to a solution of sulfuric acid with a mass of 100 g and a mass fraction of 23% is approximately 8.97 liters.

Please note that this calculation assumes ideal gas behavior and that the reaction goes to completion. In reality, there may be other factors that can affect the actual volume of gas evolved.