Question

из раствора массой 3 кг с массовой долей аммиачной селитра 20% при охлаждении выпало 100г соли. определите массовую долю соли в охлажденном растворе

Answer 1

всего было селитры в растворе 0,2*3000=600 г
100 г выпало. Осталось 500 г селитры в растворе. Соответственно и сам раствор полегчал на те же 100 г и весит теперь 3000-100=2900 г
массовая доля = 500/2900=0,1724  (17,24%) Ответ.

Answer 2

Calculation of the Mass Fraction of Salt in the Cooled Solution

To determine the mass fraction of salt in the cooled solution, we need to use the given information about the initial solution and the amount of salt that precipitated during cooling.

Given: - Mass of the solution = 3 kg - Mass fraction of ammonium nitrate (NH4NO3) in the solution = 20% - Mass of salt precipitated during cooling = 100 g

To find the mass fraction of salt in the cooled solution, we can follow these steps:

1. Calculate the mass of ammonium nitrate (NH4NO3) in the initial solution: - Mass of ammonium nitrate = Mass of the solution * Mass fraction of ammonium nitrate - Mass of ammonium nitrate = 3 kg * 20% = 0.6 kg

2. Calculate the mass of the remaining solution after the salt precipitated: - Mass of the remaining solution = Mass of the solution - Mass of salt precipitated - Mass of the remaining solution = 3 kg - 0.1 kg = 2.9 kg

3. Calculate the mass of salt in the cooled solution: - Mass of salt in the cooled solution = Mass of the solution - Mass of the remaining solution - Mass of salt in the cooled solution = 3 kg - 2.9 kg = 0.1 kg

4. Calculate the mass fraction of salt in the cooled solution: - Mass fraction of salt = Mass of salt in the cooled solution / Mass of the remaining solution - Mass fraction of salt = 0.1 kg / 2.9 kg = 0.0345 (rounded to four decimal places)

Therefore, the mass fraction of salt in the cooled solution is approximately 0.0345 or 3.45%.

Please note that the calculations assume that the mass of the solution remains constant during the cooling process and that there are no other components present in the solution that could affect the mass fraction of salt.