Question

A chemist determines that 0.54 g of oxygen reacts with 1.26 g of iron and forms rust in a lab experiment. Which of the following pairs correctly represents the percent composition of each element in the new compound?Fe = 40% and O = 60%Fe = 60% and O = 40%Fe = 50% and O = 50%Fe = 70% and O = 30%

Answer 1

ANSWER

EXPLANATION

Given that;

The mass of oxygen is 0.54g

The mass of iron is 1.26g

Follow the steps below to find the percent composition of each element in the compound

Step 1; Define a compound

A compound is the combination of two of more elements that are chemically combined together

i.e., Iron + oxygen = Iron oxide

Step 2; Find the total mass of the compound

The total mass of the compound is calculated below as

Total mass = 0.54 + 1.26

Total mass = 1.8 grams

Step 3; Find the percent composition of each element by using the below formula

$\text{ \% composition of the element = }\frac{\text{ mass of the element}}{\text{ total mass of the compound}}\times\text{ 100\%}$$\begin{gathered} \text{ For oxygen} \\ \text{ \% composition of oxygen = }\frac{\text{ 0.54 }}{\text{ 1.8}}\times\text{ 100\%} \\ \\ \text{ \% composition of oxygen = 0.3 }\times\text{ 100\%} \\ \text{ \% composition of oxygen = 30\%} \\ \\ \\ \text{ For iron} \\ \text{ \% composition of iron = }\frac{\text{ 1.26}}{\text{ 1.8}}\times\text{ 100\%} \\ \\ \text{ \% composition of iron = 0.7 }\times\text{ 100\%} \\ \text{ \% composition of iron = 70\%} \end{gathered}$

Therefore, the composition of Fe is 70% and the percent composition of O is 30