Question

В 1060 г 2%-ного раствора карбоната натрия растворили 14,3 г кристаллической соды(Na2CO3*10H2O). вычислите массовую долю в полученном растворе. Вычислите объем углекислого газа , который образуется при взаимодействии полученного раствора с избытком соляной кислоты.

Answer 1

Дано:
m(р-раNa2CO3)=1060г
w(Na2CO3)=2%=0.02
m(Na2CO3*10H2O)=14.3г
Найти:
w(Na2CO3)-?
V(CO2)-?
Решение:
m(Na2CO3)=m(р-раNa2CO3)*w(Na2CO3)=1060*0.02=21.2г
М(Na2CO3*10H2O)=286г/моль
n(Na2CO3*10H2O)=m/M=14.3/286=0.05моль
M(Na2CO3)=106г/моль
m(Na2CO3)=n*M=0.05*106=5.3г
w=m(в-ва)/m(р-ра)
m(в-ваNa2CO3)=5.3+21.2=26.5г
m(р-раNa2CO3)=1060+14.3=1074.3г
w(Na2CO3)=m(в-ва)/m(р-ра)=26.5/1074.3=0.025=2.5%
Na2CO3+2HCl=2NaCl+CO2+H2O
n(Na2CO3)=m/M=26.5/106=0.25моль
По реакции n(Na2CO3)=n(CO2)=0.25моль
V(CO2)=n*Vm=0.25*22.4=5.6л
Ответ: w(Na2CO3)=2.5%;V(CO2)=5.6л

Answer 2

Calculation of Mass Fraction in the Solution

To calculate the mass fraction in the solution, we need to determine the mass of the sodium carbonate (Na2CO3) in the solution and divide it by the total mass of the solution.

Given: - Mass of crystalline soda (Na2CO3·10H2O) = 14.3 g - Concentration of the sodium carbonate solution = 2%

To calculate the mass of sodium carbonate in the solution, we can use the following formula:

Mass of Na2CO3 = Mass of crystalline soda / (1 + Concentration of the sodium carbonate solution)

Substituting the given values:

Mass of Na2CO3 = 14.3 g / (1 + 0.02)

Now we can calculate the mass fraction:

Mass fraction = (Mass of Na2CO3 / Total mass of the solution) * 100%

Let's calculate the mass fraction:

Mass of Na2CO3 = 14.3 g / (1 + 0.02) = 14.3 g / 1.02 = 14.02 g

Total mass of the solution = Mass of Na2CO3 + Mass of the solvent

Since the concentration of the sodium carbonate solution is 2%, we know that 2 g of Na2CO3 is present in 100 g of the solution. Therefore, the mass of the solvent (water) can be calculated as:

Mass of the solvent = Total mass of the solution - Mass of Na2CO3 = 100 g - 14.02 g = 85.98 g

Now we can calculate the mass fraction:

Mass fraction = (14.02 g / (14.02 g + 85.98 g)) * 100% = 14.02%

Therefore, the mass fraction of sodium carbonate in the obtained solution is approximately 14.02%.