Question

Углеводород,плотность паров которого по водороду равна 39,содердит 92,31% углерода. Найдите его молекулярную формулу.

Answer 1

Найдем молекулярную массу углеводорода:

Mr(CxHy)=39*2=78 г/моль

n(C)=Mr*омега(загнутая w)(C)/(Ar(C)*100)=78*92.31/1200=6

n(H)=Mr*омега(загнутая w)(H)/(Ar(H)*100)=78*7.69/100=6

Cледовательно формула С6Н6(бензол)

Answer 2

Finding the Molecular Formula of a Hydrocarbon

To find the molecular formula of a hydrocarbon with a vapor density of 39 compared to hydrogen and containing 92.31% carbon, we can use the given information to calculate the molecular formula.

Step 1: Calculate the Number of Carbon Atoms The first step is to calculate the number of carbon atoms in the molecule. We can use the percentage of carbon in the hydrocarbon to do this.

From the given information: - Percentage of carbon (C) = 92.31% - Percentage of hydrogen (H) = 100% - 92.31% = 7.69%

Using the molar mass of carbon (12 g/mol) and hydrogen (1 g/mol), we can calculate the number of carbon atoms (N(C)) and the number of hydrogen atoms (N(H)) in the molecule.

From Source - N(C) = 92.31 / 12 ≈ 7 - N(H) = 7.69 / 1 ≈ 8

Step 2: Calculate the Molecular Formula Now that we have the number of carbon and hydrogen atoms, we can calculate the molecular formula of the hydrocarbon.

The molar mass of the hydrocarbon can be calculated using the given vapor density compared to hydrogen.

From Source - Vapor density of the hydrocarbon = 39

The molar mass of the hydrocarbon (Mr) can be calculated using the formula: Mr = vapor density * 2

From the given vapor density: - Mr = 39 * 2 = 78 g/mol

The molecular formula can be calculated using the molar mass and the number of carbon and hydrogen atoms.

Using the molar mass and the number of carbon and hydrogen atoms: - Molecular formula = C7H8

Therefore, the molecular formula of the hydrocarbon is C7H8.