Question

Рассчитайте массу 10 %-ного раствора гидроксида натрия, необходимую для полной нейтрализации 3,92 г серной кислоты

Answer 1

Ответ: 8г
Сначала находишь молярную массу H2SO4. (=98г). Затем количество вещества кислоты (=0,04моль). Количество вещества щёлочи в два раза меньше (=0,02моль). Находишь массу NaOH (=0,8г это чистое вещество). Затем делишь на 0,1 (10%) и получаешь ответ.

Answer 2

Calculating the Mass of 10% Sodium Hydroxide Solution Needed for Neutralizing Sulfuric Acid

To calculate the mass of a 10% sodium hydroxide solution needed to neutralize 3.92g of sulfuric acid, we can use the following steps:

1. Determine the Molar Mass of Sulfuric Acid: - The molar mass of sulfuric acid (H2SO4) is 98.079 g/mol.

2. Determine the Molar Ratio: - The balanced chemical equation for the neutralization of sulfuric acid with sodium hydroxide is: H2SO4 + 2NaOH → Na2SO4 + 2H2O - This equation shows that 1 mole of sulfuric acid reacts with 2 moles of sodium hydroxide.

3. Calculate the Amount of Sodium Hydroxide Needed: - Using the molar ratio, we can calculate the amount of sodium hydroxide needed to neutralize 3.92g of sulfuric acid.

4. Calculate the Mass of 10% Sodium Hydroxide Solution: - Once the amount of sodium hydroxide is determined, we can calculate the mass of the 10% solution needed.

Calculation Steps

1. Molar Mass of Sulfuric Acid: - The molar mass of sulfuric acid (H2SO4) is 98.079 g/mol.

2. Molar Ratio: - The molar ratio of sulfuric acid to sodium hydroxide is 1:2.

3. Amount of Sodium Hydroxide Needed: - Using the molar ratio and the given mass of sulfuric acid, we can calculate the amount of sodium hydroxide needed.

- First, we convert the mass of sulfuric acid to moles: - Moles of H2SO4 = Mass / Molar Mass - Moles of H2SO4 = 3.92g / 98.079 g/mol - Moles of H2SO4 ≈ 0.04 mol

- Since the molar ratio of H2SO4 to NaOH is 1:2, we need twice the moles of NaOH: - Moles of NaOH needed = 2 * Moles of H2SO4 - Moles of NaOH needed ≈ 2 * 0.04 mol - Moles of NaOH needed ≈ 0.08 mol

4. Mass of 10% Sodium Hydroxide Solution: - The mass of the 10% sodium hydroxide solution can be calculated using the concentration and the moles of NaOH needed.

- The concentration of the solution is 10%, which means 10g of NaOH is present in 100g of the solution.

- Mass of NaOH in the solution = (10/100) * Moles of NaOH needed - Mass of NaOH in the solution ≈ (10/100) * 0.08 mol - Mass of NaOH in the solution ≈ 0.008g

Therefore, the mass of the 10% sodium hydroxide solution needed to neutralize 3.92g of sulfuric acid is approximately 0.008g.