Question

Смешали 162,5г 5% раствора хлорида железа(3) и 85мл 5% раствора нитрата свинца(2) с плотностью 1,2г/мл. Определите массовые доли веществ в растворе.

Answer 1

m(FeCl3)=162,5*0,05=8,125

m р-ра 2= 85*1,2=102

m(Pb(NO3)2)=85*1,2*0,05=5,1

w(FeCl3)=8,125/ (162+102)=0,031

w(Pb(NO3)2)=5,1/(162+102)=0,019

Answer 2

Calculation of Mass Fractions in the Solution

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

Given: - Mass of 5% iron chloride (FeCl3) solution = 162.5 g - Mass of 5% lead nitrate (Pb(NO3)2) solution = 85 ml - Density of the lead nitrate solution = 1.2 g/ml

To calculate the mass fractions, we need to find the masses of iron chloride and lead nitrate in the solution.

Mass of Iron Chloride (FeCl3)

The concentration of the iron chloride solution is given as 5%. This means that 5 g of iron chloride is present in 100 ml of the solution.

To calculate the mass of iron chloride in the given solution, we can use the following formula:

Mass of Iron Chloride = (Volume of Solution) x (Concentration of Iron Chloride)

Given: - Volume of iron chloride solution = 162.5 g - Concentration of iron chloride = 5%

Using the formula, we can calculate the mass of iron chloride:

Mass of Iron Chloride = 162.5 g x (5/100) = 8.125 g.

Mass of Lead Nitrate (Pb(NO3)2)

The concentration of the lead nitrate solution is also given as 5%. This means that 5 g of lead nitrate is present in 100 ml of the solution.

To calculate the mass of lead nitrate in the given solution, we need to convert the volume of the solution to mass using the density.

Mass of Lead Nitrate = (Volume of Solution) x (Density of Solution)

Given: - Volume of lead nitrate solution = 85 ml - Density of lead nitrate solution = 1.2 g/ml

Using the formula, we can calculate the mass of lead nitrate:

Mass of Lead Nitrate = 85 ml x 1.2 g/ml = 102 g.

Mass Fractions of Substances

Now that we have the masses of iron chloride and lead nitrate, we can calculate the mass fractions of each substance in the solution.

The total mass of the solution is the sum of the masses of iron chloride and lead nitrate:

Total Mass of Solution = Mass of Iron Chloride + Mass of Lead Nitrate

Total Mass of Solution = 8.125 g + 102 g = 110.125 g.

To calculate the mass fraction of each substance, we divide the mass of the substance by the total mass of the solution and multiply by 100.

Mass Fraction of Iron Chloride = (Mass of Iron Chloride / Total Mass of Solution) x 100

Mass Fraction of Iron Chloride = (8.125 g / 110.125 g) x 100 = 7.38%.

Mass Fraction of Lead Nitrate = (Mass of Lead Nitrate / Total Mass of Solution) x 100

Mass Fraction of Lead Nitrate = (102 g / 110.125 g) x 100 = 92.62%.

Therefore, the mass fractions of iron chloride and lead nitrate in the solution are approximately 7.38% and 92.62%, respectively.

Please note that the calculations are approximate due to rounding off the values.