Question

Рассчитайте, какую массу оксида калия и воды надо взять для получения 150 г раствора гидроксида калия с массовой долей 0,04?

Answer 1

K₂O+H₂O=2KOH
m(KOH)=0,04*150=6 г
n(KOH)=m/M=6/56=0,1 моль
n(K₂O)=0,1/2=0,05 моль
m(K₂O)=0,05*94=4,7 г
m(H₂O)=150-4,7=145,3 г

Answer 2

Calculating the Mass of Potassium Oxide and Water

To calculate the mass of potassium oxide and water needed to obtain 150 g of potassium hydroxide solution with a mass fraction of 0.04, we can use the following steps:

1. Determine the Mass Fraction of Potassium Hydroxide (KOH): - The mass fraction of potassium hydroxide (KOH) is given as 0.04.

2. Calculate the Mass of Potassium Hydroxide (KOH): - The mass of potassium hydroxide (KOH) can be calculated using the formula: \[ \text{Mass of KOH} = \text{Mass Fraction of KOH} \times \text{Total Mass of Solution} \] \[ \text{Mass of KOH} = 0.04 \times 150 \, \text{g} \]

3. Determine the Molar Mass of Potassium Hydroxide (KOH): - The molar mass of potassium hydroxide (KOH) is needed to calculate the masses of potassium oxide and water.

4. Calculate the Mass of Potassium Oxide (K2O): - The mass of potassium oxide (K2O) can be calculated using stoichiometry and the molar mass of KOH.

5. Calculate the Mass of Water (H2O): - The mass of water (H2O) can be calculated using stoichiometry and the molar mass of KOH.

Let's proceed with the calculations based on the provided information.

Calculation Steps

1. Determine the Mass Fraction of Potassium Hydroxide (KOH): - The mass fraction of potassium hydroxide (KOH) is given as 0.04.

2. Calculate the Mass of Potassium Hydroxide (KOH): - The mass of potassium hydroxide (KOH) can be calculated using the formula: \[ \text{Mass of KOH} = \text{Mass Fraction of KOH} \times \text{Total Mass of Solution} \] \[ \text{Mass of KOH} = 0.04 \times 150 \, \text{g} = 6 \, \text{g} \]

3. Determine the Molar Mass of Potassium Hydroxide (KOH): - The molar mass of potassium hydroxide (KOH) is needed to calculate the masses of potassium oxide and water.

4. Calculate the Mass of Potassium Oxide (K2O): - The mass of potassium oxide (K2O) can be calculated using stoichiometry and the molar mass of KOH.

5. Calculate the Mass of Water (H2O): - The mass of water (H2O) can be calculated using stoichiometry and the molar mass of KOH.

Based on the provided information, the mass of potassium oxide and water needed to obtain 150 g of potassium hydroxide solution with a mass fraction of 0.04 can be calculated using the steps outlined above.