Question

A compound is made by carbon, hydrogena and nitrogen and 1 g of this compound contains 91.5 mg of hydrogen and 424 mg of nitrogen. What is the molecular formula given that the molar mass is about 65 g/mol? (write the formula with elements in this sequence HNO)

Answer 1

C₄H₃N

Step-by-step explanation:

To solve this question we must find the moles of each atom in order to find the empirical formula (Simplest ratio of atoms present in a molecule). With empirical formula and the molar mass of the compound we can find the molecular formula as follows:

Moles H:

91.5mg H * (1mmol / 1mg) =

91.5mmol H

Moles N:

424mg N * (1mmol / 14mg) =

30.286mmol N

The ratio of moles regard to moles N (The lower number of moles is:

H = 91.5mmolH / 30.286mmolN = 3.0

N = 30.286mmolN / 30.286mmolN = 1

empirical formula = CₓH₃N

The molar mass of this formula is:

12*x + 1*3 + 1*14 = 17g/mol

Solving for X:

12X + 17g/mol = 65g/mol

12X = 48g/mol

X = 4

There are 4 atoms of carbon and molecular formula is:

C₄H₃N