Question

Из 200 г 40% раствора соли при охлаждении выпала соль, массой 40гв полученном растворе. Чему равна массовая доля соли. ответ 25%

Answer 1

найдем сколько всего соли в растворе 0,4*200=80гр

выпало 40 гр, значит в растворе осталось 80-40=40гр

масса раствора так же уменьшилась на 40 гр

итого массовая доля равна 40/160=25%

 

Answer 2

Calculating the Mass Fraction of Salt in the Solution

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

Mass Fraction = (Mass of Salt / Total Mass of Solution) x 100%

Given: - Initial mass of the solution = 200 g - Concentration of the solution = 40% - Mass of the precipitated salt = 40 g

Using the given information, we can calculate the mass fraction of salt in the solution.

Step 1: Calculate the Initial Mass of Salt in the Solution The initial mass of salt in the solution can be calculated using the concentration of the solution.

Initial Mass of Salt = (Concentration / 100) x Initial Mass of Solution

Initial Mass of Salt = (40 / 100) x 200 g Initial Mass of Salt = 80 g

Step 2: Calculate the Total Mass of the Solution After Precipitation After the precipitation of 40 g of salt, the total mass of the solution will be:

Total Mass of Solution = Initial Mass of Solution - Mass of Precipitated Salt Total Mass of Solution = 200 g - 40 g Total Mass of Solution = 160 g

Step 3: Calculate the Mass Fraction of Salt Now, we can use the formula to calculate the mass fraction of salt in the solution:

Mass Fraction = (Mass of Salt / Total Mass of Solution) x 100% Mass Fraction = (40 g / 160 g) x 100% Mass Fraction = 25%

Therefore, the mass fraction of salt in the resulting solution is 25%.