1U7 % Comp, Emp/Molec Formulas

Front

What is an empirical formula?

Back

An empirical formula represents the simplest whole-number ratio of the elements in a compound.

Front

How do you calculate the percent composition of a compound?

Back

Percent composition is calculated by dividing the mass of each element in a compound by the total molar mass of the compound and multiplying by 100.

Front

What is the molecular formula of a compound?

Back

The molecular formula shows the actual number of atoms of each element in a molecule of the compound.

Front

How do you determine the empirical formula from percent composition?

Back

Convert the percent composition to grams, then to moles, and simplify the mole ratio to the smallest whole numbers.

Front

What is the molar mass of a compound?

Back

The molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol).

Front

How do you find the percent by mass of an element in a compound?

Back

Percent by mass is found by dividing the mass of the element by the total mass of the compound and multiplying by 100.

Front

What is the significance of the empirical formula in chemistry?

Back

The empirical formula provides insight into the composition of a compound and is useful for determining molecular formulas.

Front

How do you convert an empirical formula to a molecular formula?

Back

To convert, determine the molar mass of the empirical formula and divide the molar mass of the compound by this value to find the multiplier.

Front

What is the empirical formula for a compound with 40% carbon, 6.67% hydrogen, and 53.33% oxygen?

Back

The empirical formula is CH2O.

Front

What is the percent by mass of oxygen in water (H2O)?

Back

The percent by mass of oxygen in water is approximately 88.8%.