Percent Composition and Empirical Formulas

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 a compound?

Back

To calculate percent composition, use the formula: \( \text{Percent Composition} = \left( \frac{\text{mass of element}}{\text{molar mass of compound}} \right) \times 100 \)

Front

What is the empirical formula?

Back

The empirical formula is the simplest whole-number ratio of elements in a compound.

Front

How do you determine the empirical formula from the molecular formula?

Back

To determine the empirical formula, divide the subscripts in the molecular formula by their greatest common divisor.

Front

What is the percent by mass of sodium in NaCl?

Back

39%.

Front

What is the percent composition of CaCl₂?

Back

Ca: 36.11%; Cl: 63.88%.

Front

What is the empirical formula for N₂S₃?

Back

N₂S₃.

Front

What is the empirical formula for the compound with molecular formula X₆Y₃?

Back

X₂Y.

Front

What is the percent composition of Benzene, C₆H₆?

Back

C = 92.2%; H = 7.8%.

Front

What is the molar mass of NaCl?

Back

The molar mass of NaCl is approximately 58.44 g/mol.