Determine the molecular formula of an oxide of iron in which the mass percent of iron and oxygen are `69.9` and `30.1`, respectively.(molecular mass is 159.8).

Explanation

To determine the molecular formula of the iron oxide based on the given mass percentages of iron and oxygen, we can follow these steps:

### Step 1: Assume a Sample Size
Assume a sample size of 100 grams of the iron oxide. This simplifies the calculations since the percentages can be directly converted to grams.

### Step 2: Calculate the Mass of Each Element
From the assumed 100 grams:
- Mass of Iron (Fe) = 69.9 grams (from the percentage of iron)
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