Empirical Formulas

Front

What is an empirical formula?

Back

An empirical formula is the simplest whole-number ratio of atoms of each element in a compound.

Front

How do you calculate the empirical formula from percentage composition?

Back

1. Convert percentages to grams (assume 100g total). 2. Convert grams to moles using atomic masses. 3. Divide by the smallest number of moles to find the ratio.

Front

What is the empirical formula for a compound with 23.3% Co, 25.3% Mo, and 51.4% Cl?

Back

Co₃Mo₂Cl₁₁

Front

What is the empirical formula for a compound with 77.27% U, 10.4% O, and 12.3% F?

Back

UO₂F₂

Front

What is the empirical formula for a compound with 27.7% Mg, 23.6% P, and 48.7% O?

Back

Mg₃(PO₄)₂

Front

What is the empirical formula for a compound with 52.14% C, 13.13% H, and 34.73% O?

Back

CH₃CH₂OH

Front

How do you find the mass of an element in a compound from its percentage?

Back

Multiply the total mass of the compound by the percentage (as a decimal) of the element.

Front

If a compound contains 3.245 g of titanium and chlorine, how do you find the empirical formula?

Back

Calculate the mass of chlorine by subtracting the mass of titanium from the total mass, then find the mole ratio.

Front

What is the empirical formula for a compound with 0.819 g of titanium in a 3.245 g sample?

Back

TiCl₄

Front

What is the significance of the empirical formula in chemistry?

Back

It provides the simplest ratio of elements in a compound, which is useful for understanding its composition.