Question

Смешали 200 г 20%-ного раствора NаОН с 218 мл 10%-ного раствора того же вещества (p = 1,11 г/мл). Массовая доля щелочи в полученном растворе. …% (Запишите число с точностью до десятых).

Answer 1

Ответ:

14.5%

Объяснение:

m(NaOH)=(200*0.2)+(218*1.11*0.1)=64,198 грамма

m(Р-ра)=200+218*1,11=441,98 грамма

W(NaOH)=64.198/441.98=0,1452 - 14.52%

Answer 2

Calculation of the Mass Fraction of Alkali in the Solution

To calculate the mass fraction of alkali in the solution, we need to consider the amounts and concentrations of the two solutions that were mixed together.

Let's denote the following variables: - m1: mass of the 20% NaOH solution (200 g) - c1: concentration of the 20% NaOH solution (20%) - m2: mass of the 10% NaOH solution (218 ml) - c2: concentration of the 10% NaOH solution (10%) - p: density of the solution (1.11 g/ml)

First, we need to convert the volume of the 10% NaOH solution to mass using its density: m2 = V2 * p = 218 ml * 1.11 g/ml = 241.98 g

Next, we can calculate the total mass of the resulting solution: m_total = m1 + m2 = 200 g + 241.98 g = 441.98 g

To find the mass fraction of alkali in the resulting solution, we need to determine the total mass of alkali in the solution. This can be calculated by summing the masses of alkali from each solution.

For the 20% NaOH solution: m_alkali_1 = m1 * c1 = 200 g * 0.2 = 40 g

For the 10% NaOH solution: m_alkali_2 = m2 * c2 = 241.98 g * 0.1 = 24.198 g

The total mass of alkali in the resulting solution is: m_alkali_total = m_alkali_1 + m_alkali_2 = 40 g + 24.198 g = 64.198 g

Finally, we can calculate the mass fraction of alkali in the resulting solution: mass fraction of alkali = (m_alkali_total / m_total) * 100%

Substituting the values: mass fraction of alkali = (64.198 g / 441.98 g) * 100% ≈ 14.53%

Therefore, the mass fraction of alkali in the resulting solution is approximately 14.53%.