U6 Day 2 Warm up - Percent Composition by Mass

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 by mass of an element in a compound?

Back

Percent composition = (mass of element / total mass of compound) x 100.

Front

If a compound contains 40g of calcium, 12g of carbon, and 48g of oxygen, what is the total mass of the compound?

Back

Total mass = 40g + 12g + 48g = 100g.

Front

What is the percent composition by mass of calcium in the compound with 40g of calcium?

Back

Percent composition of calcium = (40g / 100g) x 100 = 40%.

Front

A compound contains 24g of carbon, 4g of hydrogen, and 32g of oxygen. What is the total mass of the compound?

Back

Total mass = 24g + 4g + 32g = 60g.

Front

What is the percent composition by mass of hydrogen in the compound with 4g of hydrogen?

Back

Percent composition of hydrogen = (4g / 60g) x 100 = 6.67% (approximately 7%).

Front

What is the molecular formula of carbon dioxide (CO2)?

Back

The molecular formula of carbon dioxide is CO2, consisting of one carbon atom and two oxygen atoms.

Front

What is the molar mass of carbon dioxide (CO2)?

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Molar mass of CO2 = 12.01 g/mol (C) + 2 x 16.00 g/mol (O) = 44.01 g/mol.

Front

What is the percent composition by mass of carbon in carbon dioxide (CO2)?

Back

Percent composition of carbon = (12.01g / 44.01g) x 100 = 27.3%.

Front

If a compound sample has a total mass of 180 grams and is composed of 40% carbon, what is the mass of carbon in the compound?

Back

Mass of carbon = 40% of 180g = 0.40 x 180g = 72g.