Question

1. К 300г 20-%-ного раствора хлорида натрия добавили 30 г воды. Определите массовую долю соли в полученном растворе.

Answer 1

Объяснение:

Дано: m1 = 200г

w1 = 15%

m2 = 40г

Решение:

1.)m3 = (w1 × m1) : 100% (лучше дробью записать)

m3 = (15% × 200г): 100% = 30г

2.) w2 = (30г:240г) ×100% = 12.5%

ответ 12.5%

все вычисления и формулы лучше записать дробью

Answer 2

Calculation of the Mass Fraction of Salt in the Solution

To determine the mass fraction of salt in the solution, we need to calculate the total mass of the resulting solution and the mass of the salt present in it.

Given: - Initial mass of the 20% sodium chloride solution = 300 g - Mass of water added = 30 g

To find the mass fraction of salt, we need to calculate the total mass of the resulting solution. This can be done by adding the mass of the initial solution and the mass of water added:

Total mass of the resulting solution = Initial mass of the solution + Mass of water added

Let's calculate the total mass of the resulting solution:

Total mass of the resulting solution = 300 g + 30 g = 330 g

Now, we need to calculate the mass of the salt in the resulting solution. Since the initial solution is a 20% sodium chloride solution, it means that 20% of its mass is sodium chloride. We can calculate the mass of the salt using the following formula:

Mass of salt = Mass fraction of salt × Total mass of the resulting solution

The mass fraction of salt can be calculated as follows:

Mass fraction of salt = (20% / 100%) = 0.20

Now, let's calculate the mass of the salt in the resulting solution:

Mass of salt = 0.20 × 330 g = 66 g

Therefore, the mass fraction of salt in the resulting solution is 66 g / 330 g = 0.20, or 20%.

Please note that the calculations provided above are based on the given information and assumptions.