Mass Percent

Front

What is mass percent?

Back

Mass percent (or percent by mass) is a way of expressing the concentration of an element in a compound, calculated as (mass of the element in the compound / total mass of the compound) x 100%.

Front

How do you calculate mass percent?

Back

To calculate mass percent, divide the mass of the specific element by the total mass of the compound and multiply by 100.

Front

What is the mass percent of aluminum in Al2(SO4)3?

Back

15.77%

Front

What is the percent by mass of oxygen in MgO?

Back

40%

Front

If a compound has a molar mass of 180 g/mol and contains 40% carbon by mass, what is the mass of carbon in one mole?

Back

72 g

Front

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

Back

Mass of element = (mass percent of element / 100) x total mass of compound.

Front

What is the mass of manganese in a 50 g sample of KMnO4 with 34.77% Mn?

Back

17.38 g

Front

Which of the following is NOT needed to calculate percent composition?

Back

Avogadro's Number.

Front

What is the significance of molar mass in calculating mass percent?

Back

Molar mass is used to determine the total mass of the compound, which is essential for calculating the mass percent of each element.

Front

What is the mass percent of potassium in KMnO4?

Back

20.34%.