Question

Оксид кальция массой 2,8г растворили в 200г соляной кислоты. Рассчитайте массовую долю хлороводородной кислоты в исходном растворе​

Answer 1

Ответ:

Объяснение:

Уравнение реакции:

$CaO+2HCl=CaCl_{2} +H_{2} O$

Количество вещества оксида кальция равно:

n(CaO)=m(CaO)/M(CaO)=2.8/56= 0.05(моль).

По уравнению реакции:

$\frac{n(CaO)}{n(HCl)} =\frac{1}{2}$, следовательно, количество вещества хлороводорода равно 2*n(CaO)=2*0,05=0,1(моль).

Масса хлороводорода:

m(HCl)= n(HCl)M(HCl)=0.1*36.5=3.65 (г).

Массовая доля хлороводорода:

ω=$\frac{m(HCl)}{m(p-pa)} *100%=\frac{3.65}{200} *100=1.825%$=3.65/200*100%=1.825%.

Answer 2

Calculation of the Mass Fraction of Hydrochloric Acid in the Initial Solution

To calculate the mass fraction of hydrochloric acid in the initial solution, we need to determine the amount of hydrochloric acid present in the solution and the total mass of the solution.

Given: - Mass of calcium oxide (CaO) = 2.8 g - Mass of hydrochloric acid (HCl) = 200 g

To find the mass fraction of hydrochloric acid, we need to calculate the mass of hydrochloric acid and the total mass of the solution.

1. Calculate the mass of hydrochloric acid: - The molar mass of calcium oxide (CaO) is 56.08 g/mol. - The molar mass of hydrochloric acid (HCl) is 36.46 g/mol. - We can use the molar ratio between CaO and HCl to calculate the mass of HCl. - The molar ratio between CaO and HCl is 1:2, meaning that for every 1 mole of CaO, we have 2 moles of HCl. - First, we need to convert the mass of CaO to moles: - Moles of CaO = Mass of CaO / Molar mass of CaO - Moles of CaO = 2.8 g / 56.08 g/mol - Next, we can use the molar ratio to calculate the moles of HCl: - Moles of HCl = Moles of CaO * (2 moles of HCl / 1 mole of CaO) - Finally, we can convert the moles of HCl to mass: - Mass of HCl = Moles of HCl * Molar mass of HCl

2. Calculate the total mass of the solution: - The total mass of the solution is the sum of the mass of calcium oxide and the mass of hydrochloric acid.

3. Calculate the mass fraction of hydrochloric acid: - The mass fraction of hydrochloric acid is the ratio of the mass of hydrochloric acid to the total mass of the solution, multiplied by 100 to express it as a percentage.

Let's perform the calculations:

1. Calculate the mass of hydrochloric acid: - Moles of CaO = 2.8 g / 56.08 g/mol = 0.0499 mol - Moles of HCl = 0.0499 mol * (2 mol HCl / 1 mol CaO) = 0.0998 mol - Mass of HCl = 0.0998 mol * 36.46 g/mol = 3.64 g

2. Calculate the total mass of the solution: - Total mass of the solution = Mass of CaO + Mass of HCl = 2.8 g + 3.64 g = 6.44 g

3. Calculate the mass fraction of hydrochloric acid: - Mass fraction of HCl = (Mass of HCl / Total mass of the solution) * 100 - Mass fraction of HCl = (3.64 g / 6.44 g) * 100 = 56.6%

Therefore, the mass fraction of hydrochloric acid in the initial solution is approximately 56.6%.