When you're figuring out empirical formulas in science class, it's easy to make some common mistakes. Here are a few things to watch out for:

1. Wrong Molar Ratios: Sometimes, students mix up how to find the moles of each element. For example, if you have 4 grams of carbon (C) and 32 grams of oxygen (O), you can't just use the weight to get the ratio. Instead, you need to convert grams into moles first:

   • Moles of C = $4 \text{ g} / 12.01 \text{ g/mol} \approx 0.33$
   • Moles of O = $32 \text{ g} / 16.00 \text{ g/mol} = 2$.

2. Not Simplifying Ratios: When you find a ratio like 1:6, don’t assume that’s the final answer. You need to simplify it to whole numbers. To do this, divide each number by the smallest mole value you found. In this case:

   • Divide both by 0.33: $1:6$ stays as $1:6$.

3. Forgetting About Percent Composition: Some students forget to change percentages into grams before dividing by molar masses. For example, if you have a compound made up of 40% carbon and 60% oxygen, treat it like you have 100 grams of the mix.

By keeping these points in mind, you’ll be able to find the right empirical formula more easily!