Question

What is the molar mass of a compound represented below?

• A. 128 g/mol
• B. 108 g/mol
• C. 120 g/mol
• D. 126 g/mol

Hint:

When calculating the molar mass of a compound, sum the atomic masses of all atoms present in the molecular formula.

Answer 1

The Correct Option is A

Step 1: Analyzing the compound.
The compound contains an ethyl group (Et) and a methyl group (Me). The structure consists of an ethyl group (C$_2$H$_5$) and a methyl group (CH$_3$) attached to a carbon-carbon chain. The molar mass of the compound is calculated by adding the atomic masses of the constituent atoms.
Step 2: Calculation.
For the ethyl group (Et): \[ \text{Molar mass of Et} = 2 \times 12 + 5 \times 1 = 29 \, \text{g/mol} \] For the methyl group (Me): \[ \text{Molar mass of Me} = 1 \times 12 + 3 \times 1 = 15 \, \text{g/mol} \] For the entire compound: \[ \text{Molar mass of compound} = 29 + 15 + 84 = 128 \, \text{g/mol} \] Step 3: Conclusion.
The correct molar mass of the compound is 128 g/mol, so the correct answer is (A).