Percent Composition

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 carbon monoxide (CO)?

Back

The molar mass of CO is approximately 28.01 g/mol (12.01 g/mol for C + 16.00 g/mol for O).

Front

What is the percent composition of carbon in carbon monoxide (CO)?

Back

The percent composition of carbon in CO is (12.01 g/mol / 28.01 g/mol) x 100 = 42.8%, approximately 43%.

Front

What is the molar mass of magnesium bromide (MgBr2)?

Back

The molar mass of MgBr2 is approximately 200.89 g/mol (24.31 g/mol for Mg + 2 x 79.90 g/mol for Br).

Front

How do you find the percent composition of bromine in magnesium bromide (MgBr2)?

Back

The percent composition of bromine in MgBr2 is (2 x 79.90 g/mol / 200.89 g/mol) x 100 = 79.4%, approximately 87%.

Front

What is the molar mass of lithium phosphide (Li3P)?

Back

The molar mass of Li3P is approximately 34.83 g/mol (3 x 6.94 g/mol for Li + 30.97 g/mol for P).

Front

What is the percent composition of phosphorus in lithium phosphide (Li3P)?

Back

The percent composition of phosphorus in Li3P is (30.97 g/mol / 34.83 g/mol) x 100 = 88.9%, approximately 60%.

Front

What is the molar mass of calcium nitrate (Ca(NO3)2)?

Back

The molar mass of Ca(NO3)2 is approximately 164.10 g/mol (40.08 g/mol for Ca + 2 x (14.01 g/mol for N + 3 x 16.00 g/mol for O)).

Front

How do you calculate the percent composition of nitrogen in calcium nitrate (Ca(NO3)2)?

Back

The percent composition of nitrogen in Ca(NO3)2 is (2 x 14.01 g/mol / 164.10 g/mol) x 100 = 17.1%, approximately 17%.