Question

Какое количество вещества воды находится в 800 грамм водного раствора бромида калия, если массовая доля этого раствора бромида калия равна 20% и в этом растворе ничего кроме калия и воды не содержится

Answer 1

1)m(KBr)=m(р-ра)*w(KBr в р-ре)=800*0,2=160 г
2)m(H2O)=m(р-ра)-m(KBr)=800-160=640 г

Answer 2

Calculation of the Amount of Water in a Potassium Bromide Solution

To calculate the amount of water in a 800-gram solution of potassium bromide with a mass fraction of 20%, we need to determine the mass of potassium bromide and then subtract it from the total mass of the solution.

1. Calculate the mass of potassium bromide: - The mass fraction of potassium bromide is given as 20%. - This means that 20% of the solution's mass is potassium bromide. - Therefore, the mass of potassium bromide in the solution is 20% of 800 grams. - Mass of potassium bromide = 20% of 800 grams = 0.20 * 800 grams = 160 grams.

2. Calculate the mass of water: - Since the solution contains only potassium bromide and water, the remaining mass must be water. - The mass of water can be calculated by subtracting the mass of potassium bromide from the total mass of the solution. - Mass of water = Total mass of solution - Mass of potassium bromide = 800 grams - 160 grams = 640 grams.

Therefore, there are 640 grams of water in the 800-gram solution of potassium bromide with a mass fraction of 20%.

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