Question

8. Рассчитайте массовую долю аммиака в растворе, полученном растворением 6,72 л аммиака (н. у.) в 175 мл воды.​

Answer 1

Дано:

V(NH3) = 6,72 л

V(H2O) = 175 мл

Найти: w(NH3)

Решение:

m(H2O) = V(H2O) = 175 г

n(NH3) = V(NH3) / Vm = 6,72 / 22,4 = 0,3 моль (Vm = 22,4 л/моль)

m(NH3) = n(NH3) * M(NH3) = 0,3 * 17 = 5,1 г

m(р-р) = m(H2O) + m(NH3) = 175 + 5,1 = 180,1 г

w(NH3) = m(NH3) / m(р-р) = 5,1 / 180,1 = 0,0283 или 2,83%

Ответ: w(NH3) = 2,83%

Answer 2

Calculating the Mass Fraction of Ammonia in the Solution

To calculate the mass fraction of ammonia in the solution, we can use the formula:

Mass fraction = (mass of ammonia / total mass of solution) * 100%

First, we need to calculate the mass of ammonia and the total mass of the solution.

Given: Volume of ammonia (at standard conditions) = 6.72 L Volume of water = 175 mL

Calculating the Mass of Ammonia

Using the molar volume of a gas at standard conditions (22.4 L/mol), we can calculate the number of moles of ammonia and then its mass.

Step 1: Calculate the moles of ammonia Moles of ammonia = (Volume of ammonia at standard conditions) / (Molar volume of gas at standard conditions) Moles of ammonia = 6.72 L / 22.4 L/mol

Step 2: Calculate the mass of ammonia The molar mass of ammonia (NH3) is approximately 17 g/mol. Mass of ammonia = Moles of ammonia * Molar mass of ammonia

Calculating the Total Mass of the Solution

We need to convert the volume of water to liters and then calculate the total mass of the solution.

Step 3: Convert the volume of water to liters Volume of water = 175 mL = 0.175 L

Step 4: Calculate the total mass of the solution Assuming the density of water is approximately 1 g/mL, the mass of water can be calculated as: Mass of water = Volume of water * Density of water

Calculating the Mass Fraction of Ammonia

Now that we have the mass of ammonia and the total mass of the solution, we can calculate the mass fraction of ammonia in the solution using the formula mentioned at the beginning.

I will now calculate the mass of ammonia and the total mass of the solution using the given information and then proceed to calculate the mass fraction of ammonia in the solution.