Question

Вычислите мольную долю нитрата натрия и мольную долю воды в растворе с массовой долей NaNO3 10%

Answer 1

Решение. w(NaNO3)=10%. В 100 г раствора:
m(NaNO3)=10 г; m(H2O)=90 г.
Молярные массы веществ:
M(NaNO3) = 23+14+3*16=87 г/моль;
M(H2O) = 1*2+16=18 г/моль.
Количество веществ в растворе:
n(NaNO3)= m(NaNO3) =  10 = 0.11 моль
                  M(NaNO3)     87

n(H2O)=m(H2O)  =90 = 5моль
             M(H2O)   18

с(NaNO3)=   n(NaNO3)            =   0,11 моль              = 0,02
                  n(NaNO3)+n(H2O)      0,11 моль+5 моль

с(H2O)=       n(H2O)            =          5____________  =   0,98      
              n(NaNO3)+n(H2O)      0,11 моль+5 моль

с(NaNO3)+с(H2O)=0,02+0,98=1
Сумма мольных долей всех веществ равна единице.

Answer 2

Calculation of Molar Fraction of Sodium Nitrate (NaNO3)

To calculate the molar fraction of sodium nitrate (NaNO3) in a solution with a mass fraction of 10%, we need to consider the molar masses of NaNO3 and water (H2O).

The molar mass of NaNO3 is calculated as follows: - Molar mass of Na = 22.99 g/mol - Molar mass of N = 14.01 g/mol - Molar mass of O (3 atoms) = 16.00 g/mol - Total molar mass of NaNO3 = (22.99 g/mol) + (14.01 g/mol) + (16.00 g/mol * 3) = 85.00 g/mol

The molar mass of water (H2O) is calculated as follows: - Molar mass of H (2 atoms) = 1.01 g/mol - Molar mass of O = 16.00 g/mol - Total molar mass of H2O = (1.01 g/mol * 2) + (16.00 g/mol) = 18.02 g/mol

To calculate the molar fraction of NaNO3, we need to determine the number of moles of NaNO3 and water in the solution.

Let's assume we have 100 grams of the solution. The mass of NaNO3 in the solution is 10% of 100 grams, which is 10 grams. The mass of water in the solution is the remaining 90 grams.

To calculate the number of moles of NaNO3 and water, we divide their masses by their respective molar masses:

- Moles of NaNO3 = (10 g) / (85.00 g/mol) = 0.1176 mol - Moles of H2O = (90 g) / (18.02 g/mol) = 4.9967 mol

The molar fraction of NaNO3 is the ratio of moles of NaNO3 to the total moles of all components in the solution:

- Molar fraction of NaNO3 = (0.1176 mol) / (0.1176 mol + 4.9967 mol) = 0.0229

Therefore, the molar fraction of NaNO3 in the solution is approximately 0.0229.

Calculation of Molar Fraction of Water (H2O)

To calculate the molar fraction of water (H2O) in the solution, we can use the same information as above.

The molar fraction of water is the ratio of moles of water to the total moles of all components in the solution:

- Molar fraction of H2O = (4.9967 mol) / (0.1176 mol + 4.9967 mol) = 0.9771

Therefore, the molar fraction of water in the solution is approximately 0.9771.

Please note that these calculations assume ideal behavior and do not take into account any interactions between the solute and solvent molecules.