Percent Composition by Mass Problems

Front

What is percent composition by mass?

Back

Percent composition by mass is the percentage by mass of each element in a compound, calculated by dividing the mass of the element by the total mass of the compound and multiplying by 100.

Front

How do you calculate the percent composition of an element in a compound?

Back

To calculate the percent composition of an element, use the formula: \( \text{Percent Composition} = \left( \frac{\text{mass of element}}{\text{total mass of compound}} \right) \times 100 \)

Front

What is the percent composition by mass of hydrogen in a compound containing 24g of carbon, 4g of hydrogen, and 32g of oxygen?

Back

7%.

Front

What is the percent composition by mass of nitrogen in ammonia (NH₃)?

Back

82.2%.

Front

What is the percent composition of carbon and hydrogen in benzene (C₆H₆)?

Back

C = 92.2%, H = 7.8%.

Front

What is the percent composition by mass of oxygen in water (H₂O)?

Back

89%.

Front

If a compound sample contains 40g of calcium, 12g of carbon, and 48g of oxygen, what is the percent composition by mass of calcium?

Back

40%.

Front

What is the total mass of a compound if it contains 24g of carbon, 4g of hydrogen, and 32g of oxygen?

Back

60g.

Front

How do you find the total mass of a compound?

Back

Add the masses of all elements in the compound together.

Front

What is the formula for calculating the mass of an element in a compound?

Back

Mass of element = (Percent Composition / 100) × Total mass of compound.