Question

Practical work

1. What is the mass of a solution of sulfuric acid with a mass fraction of it in the solution of 96%
spent on dissolving copper scrap weighing 12.8 g, which contained 0.5 parts by mass of copper?
2. What volume of ammonia can be obtained by treating ammonium chloride weighing 12 g with a solution
sodium hydroxide, which contains 8 g of it.
3. What is the practical yield of gas, if 4 liters of it were obtained by the thermal decomposition of potassium nitrate
weighing 40.4 g?
4. What is the practical yield of the sediment, if 6.5 g of it was filtered after
addition of 15 g of barium hydroxide solution with a mass fraction of 40% to orthophosphate acid
weighing 5 g.
5. How will the rate of the reaction that takes place in the gas phase change when it decreases
temperature by 30°C, if the temperature rate coefficient for this reaction is equal to 3.
6. The reaction of the decomposition of phosphorus pentachloride proceeds according to the equation:
PCl 5 (g) ↔ PCl 3 (g) + Сl 2 (g) – 92 kJ. How to change: a) temperature; b) pressure; in)
the concentration of reactants to shift the equilibrium of the reaction towards the decomposition of PCl 5 (to the right).

Answer 1

What is the mole fraction of sulfuric acid in a solution containing 98% sulfuric by mass?

What is the mole fraction of H2SO4 in a 98% aqueous H2SO4 solution?

Here given..

98 % of H2SO4 that means 98 g of H2SO4 is there in 100 g of aq. H2SO4 solution.

So.

Mass of solute = 98 g

Mass of solvent = 2 g (as water is considered as universal solvent)

Molar mass of solute = 98 g

Molar mass of solvent = 18 g

No of moles of solute = 1 mole (no of moles = given mass / molar mass)

No of moles of solvent = 2/18 = 1/9 moles

And ,

We know formula for mole fraction is..

x( of solute) = Moles of solute/(moles of solute + moles of solvent)

x (of solute) = 1/(1+(1/9)) = 0.9

x (of solvent) = 1 - 0.9 = 0.1

Step-by-step explanation:

it is just number 1