The compound A has 26.7% C, 71.1% O and 2.2%H.
if the relative molecular mass of A is 90, what is the molecular formula of A

Explanation

To determine the molecular formula of compound A, we will follow these steps:

### Step 1: Prepare a Chart
We will create a chart to organize the information given in the problem.

| Element | Percentage (%) | Molar Mass (g/mol) | Moles (mol) | Simple Ratio |
|----------|----------------|---------------------|-------------|--------------|
| Carbon (C) | 26.7 | 12 | | |
...