Question

1)При сжигании без остатка 4.3 г углеводорода получили 13.2 г оксида углерода(IV). Относительная плотность углеводорода по водороду равна 43. Выведите молекулярную формулу этого вещества. Напишите, пожалуйста с дано и решение и т.д

Answer 1

Дано:

m(CxHy) = 4,3 г

m(CO₂) = 13,2 г

D(H₂) = 43

Найти: x и y

Решение:

1) Молярная масса углеводорода:

Mr(CxHy) = D(H₂)*Mr(H₂) = 43*2 = 86 г/моль

2) Количество его:

n(CxHy) = 4,3г/86г/моль = 0,05 моль

Количество углекислого газа (совпадает с количеством углерода в нем):

n(CO₂) = 13,2/44 = 0,3 моль = n(C)

Т.е. в 0,05 моль углеводорода содержится 0,3 моль углерода (в 6 раз больше)

Это может быть углеводород с формулой C₆H₁₄

M(C₆H₁₄) = 86 г/моль

Answer 2

Given Information:

- Mass of hydrocarbon (CₓHᵧ) = 4.3 g - Mass of carbon dioxide (CO₂) produced = 13.2 g - Relative density of hydrocarbon to hydrogen = 43

Solution:

1. Calculate the moles of carbon dioxide produced: - The molar mass of CO₂ is 44 g/mol (12 g/mol for C and 32 g/mol for O). - Moles of CO₂ = Mass of CO₂ / Molar mass of CO₂ - Moles of CO₂ = 13.2 g / 44 g/mol = 0.3 mol

2. Determine the moles of carbon in the hydrocarbon: - Moles of C in CO₂ = Moles of CO₂ (since there is 1 C in 1 CO₂ molecule) - Moles of C in hydrocarbon = Moles of C in CO₂ = 0.3 mol

3. Find the moles of hydrogen in the hydrocarbon: - Moles of H in hydrocarbon = Moles of C in hydrocarbon * 2 (since the ratio of H to C in hydrocarbons is 2:1) - Moles of H in hydrocarbon = 0.3 mol * 2 = 0.6 mol

4. Calculate the molar mass of the hydrocarbon: - Molar mass of C = 12 g/mol - Molar mass of H = 1 g/mol - Molar mass of hydrocarbon = (Moles of C * Molar mass of C) + (Moles of H * Molar mass of H) - Molar mass of hydrocarbon = (0.3 mol * 12 g/mol) + (0.6 mol * 1 g/mol) = 3.6 g + 0.6 g = 4.2 g/mol

5. Determine the molecular formula of the hydrocarbon: - Relative density of hydrocarbon to hydrogen = 43 - This means the molar mass of the hydrocarbon is 43 times that of hydrogen. - Since the molar mass of hydrogen is 1 g/mol, the molar mass of the hydrocarbon is 43 g/mol. - The molar mass of the hydrocarbon calculated earlier is 4.2 g/mol. - The molecular formula of the hydrocarbon is C₂H₄.

Therefore, the molecular formula of the hydrocarbon is C₂H₄.