Question

Ненасыщенный углеводород массой 0.21 грамм может присоединить 0.80 грамм брома. Найдите его молекулярную массу.

Answer 1

Расчет такой: к х грамм-молекуле непредельного углеводорода присоединяется 160 молей брома (Br2), а к 0,21 г углеводорода - 0,8 г брома.
х=0,21*160/0,8=42. Молекулярная масса 28 соответствует пропилену С3Н6

Answer 2

Calculation of Molecular Mass

To find the molecular mass of the unsaturated hydrocarbon, we need to use the information given. According to the question, the unsaturated hydrocarbon with a mass of 0.21 grams can react with 0.80 grams of bromine.

To determine the molecular mass, we can use the concept of stoichiometry. The reaction between the unsaturated hydrocarbon and bromine can be represented as follows:

Unsaturated hydrocarbon + Bromine → Product

From the given information, we know that 0.21 grams of the unsaturated hydrocarbon reacts with 0.80 grams of bromine. To find the molecular mass, we need to determine the molar ratio between the unsaturated hydrocarbon and bromine.

The molar ratio can be calculated using the molar masses of the elements involved. The molar mass of bromine (Br) is approximately 79.90 g/mol.

Let's calculate the molar ratio:

Molar ratio = (mass of bromine) / (molar mass of bromine) = 0.80 g / 79.90 g/mol = 0.010 mol

Since the molar ratio between the unsaturated hydrocarbon and bromine is 1:1, we can conclude that the number of moles of the unsaturated hydrocarbon is also 0.010 mol.

Now, we can calculate the molecular mass of the unsaturated hydrocarbon using the formula:

Molecular mass = (mass of the unsaturated hydrocarbon) / (number of moles of the unsaturated hydrocarbon)

Molecular mass = 0.21 g / 0.010 mol = 21 g/mol

Therefore, the molecular mass of the unsaturated hydrocarbon is 21 g/mol.