Question

Для приготовления раствора смешали 700 мл воды, 12 г карбоната натрия, 15 г гидрокарбоната натрия и 10 г гидроксида натрия. Рассчитайте массовые доли веществ в получившемся растворе.

Answer 1

M(H2O)=700г
m(раствора)=700г+12г+15г+10г=737г
W(Na2CO3)=12/737=0,016
W(NaHCO3)=15/737=0,02
W(NaOH)=10/737=0,0135

Answer 2

Calculation of Mass Fractions in the Solution

To calculate the mass fractions of the substances in the solution, we need to determine the total mass of the solution and the individual masses of each substance.

Given: - Volume of water: 700 mL - Mass of sodium carbonate (Na2CO3): 12 g - Mass of sodium bicarbonate (NaHCO3): 15 g - Mass of sodium hydroxide (NaOH): 10 g

To calculate the total mass of the solution, we need to consider the density of water. The density of water is approximately 1 g/mL. Therefore, the mass of 700 mL of water is 700 g.

The total mass of the solution is the sum of the mass of water and the masses of the substances dissolved in it:

Total mass of the solution = mass of water + mass of sodium carbonate + mass of sodium bicarbonate + mass of sodium hydroxide

Total mass of the solution = 700 g + 12 g + 15 g + 10 g

Total mass of the solution = 737 g

Now, we can calculate the mass fractions of each substance in the solution:

Mass fraction of sodium carbonate (Na2CO3): Mass fraction = (mass of sodium carbonate / total mass of the solution) * 100

Mass fraction of sodium carbonate = (12 g / 737 g) * 100

Mass fraction of sodium carbonate ≈ 1.63%

Mass fraction of sodium bicarbonate (NaHCO3): Mass fraction = (mass of sodium bicarbonate / total mass of the solution) * 100

Mass fraction of sodium bicarbonate = (15 g / 737 g) * 100

Mass fraction of sodium bicarbonate ≈ 2.04%

Mass fraction of sodium hydroxide (NaOH): Mass fraction = (mass of sodium hydroxide / total mass of the solution) * 100

Mass fraction of sodium hydroxide = (10 g / 737 g) * 100

Mass fraction of sodium hydroxide ≈ 1.36%

Therefore, the mass fractions of the substances in the resulting solution are approximately: - Sodium carbonate (Na2CO3): 1.63% - Sodium bicarbonate (NaHCO3): 2.04% - Sodium hydroxide (NaOH): 1.36%

Please note that these calculations are approximate and may vary slightly depending on the actual masses and volumes used in the experiment.