Percent Composition Practice Problems

Front

What is percent composition?

Back

Percent composition is the percentage by mass of each element in a compound, calculated by dividing the mass of each 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: (mass of element in 1 mole of compound / molar mass of compound) x 100.

Front

What is the molar mass of MgBr2?

Back

The molar mass of MgBr2 is approximately 184.11 g/mol (Mg = 24.31 g/mol, Br = 79.90 g/mol).

Front

In MgBr2, which element has a higher percent composition?

Back

Bromine has a higher percent composition in MgBr2.

Front

What is the percent by mass of Mn in KMnO4?

Back

The percent by mass of Mn in KMnO4 is 35%.

Front

What is the percent composition of water (H2O)?

Back

The percent composition of water is H = 11.1% and O = 88.9%.

Front

How do you find the percent by mass of oxygen in NaOH?

Back

Calculate the molar mass of NaOH (Na = 22.99 g/mol, O = 16.00 g/mol, H = 1.01 g/mol) and use the formula for percent composition.

Front

What is the percent by mass of lithium in Li3P?

Back

The percent by mass of lithium in Li3P is 40%.

Front

What is the significance of percent composition in chemistry?

Back

Percent composition helps in understanding the composition of compounds and is essential for stoichiometric calculations.

Front

What is the percent by mass of hydrogen in H2O?

Back

The percent by mass of hydrogen in H2O is 11.1%.