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# Percent Composition

## Calculating the percentage by mass of each element in a compound.

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Practice Percent Composition

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Ingredients For Air

Credit: monkeyatlarge

Our Sky [Figure1]

### Percent Composition

Percent composition describes what something is made of, and what percent of each element is in an object. Have you ever wondered what the air around us is made out of? Our air’s composition might surprise you! Look up our air’s percent composition to answer the following questions.

### Creative Applications

1. What percent of our air is Oxygen? What percent is Carbon Dioxide?

2. What is our air mostly made of? What percent is that element? If there are 300 liters of air, how many liters of that element are present.

3. How could you determine the percent composition of an unknown simple ionic compounds, given the elements it was made out of?

### Extension:

We know that Oxygen makes up 1/5th of our atmosphere. What would happen if we didn’t have Oxygen for 5 seconds? http://www.youtube.com/watch?v=wXEjJSALaCU

### Notes/Highlights Having trouble? Report an issue.

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