Question

В 450 г воды растворили 150г кристаллогидрата карбоната натрия (Na2CO3·10H2O). Рассчитать массовую долю растворённого вещества в %.

Answer 1

Na2CO3 * 10H2O
     106 г + 180 г = 286 г
если 286 г кристаллогидрате --------- 106 г вещество (Na2CO3)
    то 150 г крист. будет       ------------- х г вещество
                    х = 150*106 : 286= 55,6 г 
                                                                            55,6
массовая доля растворённого вещества = ----------- *100%= 9,26 %
                                                                       450+150
Ответ : 9,3% 

Answer 2

Calculation of Mass Fraction of Dissolved Substance

To calculate the mass fraction of the dissolved substance in the solution, we need to determine the mass of the dissolved substance and the total mass of the solution.

Given: - Mass of water (solvent) = 450 g - Mass of sodium carbonate decahydrate (Na2CO3·10H2O) = 150 g

To calculate the mass fraction, we need to find the mass of the dissolved substance (Na2CO3·10H2O) and the total mass of the solution (water + dissolved substance).

The mass of the dissolved substance is 150 g, as given.

The total mass of the solution is the sum of the mass of water and the mass of the dissolved substance: Total mass of the solution = Mass of water + Mass of dissolved substance Total mass of the solution = 450 g + 150 g Total mass of the solution = 600 g

Now, we can calculate the mass fraction of the dissolved substance using the formula: Mass fraction = (Mass of dissolved substance / Total mass of the solution) * 100

Substituting the values: Mass fraction = (150 g / 600 g) * 100 Mass fraction = 0.25 * 100 Mass fraction = 25%

Therefore, the mass fraction of the dissolved substance (Na2CO3·10H2O) in the solution is 25%.