Question

Помогите пожалуйста! Расчитай массовую долю растворенного вещества в растворах, состоящих из: а) 200г воды и 5г NaCl б) 50г воды и 2г K2SO4 в) 500г воды и 30г сахара. Имеет ли значение при расчете, какого растворенное вещество?

Answer 1

Общая формула для расчета: w(р-ра) = m(р.в.) ∙100% \ m (р-ра)
m (р-ра) = m(р.в.) + m(воды)
а)  m (р-раNaCl) = m(NaCl) + m(воды) = 200 г + 5 г = 205 г
w(р-ра NaCl) = 5 г ∙100% \ 205 г = 2,4%
б) m (р-ра K₂SO₄) = m(K₂SO₄) + m(воды) = 50 г + 2 г = 52 г
w(р-ра K₂SO₄) = 2 г ∙100% \ 52 г = 4%
в) m (р-ра сах) = m(сах) + m(воды) = 500 г +  30 г = 530 г
w(р-ра сах) = 30 г ∙100% \ 530 г = 5,7%
 Имеет ли значение при расчете, какого растворенное вещество?
нет
имеет значение только масса растворяемого вещества и масса растворителя (воды)

Answer 2

Calculating the Mass Fraction of Solute in Solutions

To calculate the mass fraction of solute in a solution, we can use the formula:

Mass Fraction of Solute = (Mass of Solute / Total Mass of Solution) × 100%

Let's calculate the mass fraction of the solute in each of the given solutions.

Solution (a): 200g of Water and 5g of NaCl

Using the formula, we can calculate the mass fraction of NaCl in the solution:

Mass Fraction of NaCl = (5g / (200g + 5g)) × 100%

Mass Fraction of NaCl = (5g / 205g) × 100%

Mass Fraction of NaCl ≈ 2.44%

Solution (b): 50g of Water and 2g of K2SO4

Similarly, for the second solution, the mass fraction of K2SO4 can be calculated:

Mass Fraction of K2SO4 = (2g / (50g + 2g)) × 100%

Mass Fraction of K2SO4 = (2g / 52g) × 100%

Mass Fraction of K2SO4 ≈ 3.85%

Solution (c): 500g of Water and 30g of Sugar

For the third solution, the mass fraction of sugar can be calculated:

Mass Fraction of Sugar = (30g / (500g + 30g)) × 100%

Mass Fraction of Sugar = (30g / 530g) × 100%

Mass Fraction of Sugar ≈ 5.66%

Importance of the Solute in the Calculation

When calculating the mass fraction of the solute in a solution, it is important to consider the type and amount of the solute present. Different solutes have different effects on the properties of the solution, such as boiling point elevation, freezing point depression, and osmotic pressure.

In the given examples, the type of solute (NaCl, K2SO4, and sugar) determines the mass fraction and, consequently, the properties of the solution.

I hope this helps! If you have any further questions or need additional assistance, feel free to ask.