Percent composition practice

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 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

Percent composition = (mass of element in 1 mole of compound / molar mass of compound) x 100.

Front

What is the percent composition by mass of magnesium in MgSO4? (gram formula mass = 120 g/mol)

Back

20%.

Front

What is the percent by mass of sodium in NaCl?

Back

39%.

Front

What percentage of the total atomic mass of magnesium bromide (MgBr2) is composed of magnesium?

Back

13%.

Front

Find the percent composition of CaCl2.

Back

Ca: 36.11%; Cl: 63.88%.

Front

What is the percent composition by mass of oxygen in MgSO4? (gram formula mass = 120 g/mol)

Back

53%.

Front

What is the molar mass of NaCl?

Back

58.44 g/mol.

Front

If a compound has a molar mass of 100 g/mol and contains 25 g of carbon, what is the percent composition of carbon?

Back

25%.

Front

What is the percent composition of hydrogen in H2O? (molar mass = 18 g/mol)

Back

11.11%.