5.5 Percent Composition

Front

What is percent composition?

Back

Percent composition is the percentage by mass of each element in a compound, calculated using the formula: % comp = (Mass contribution from the specific element / Total mass in formula) x 100.

Front

How do you calculate the mass contribution of an element in a compound?

Back

To calculate the mass contribution of an element, multiply the number of atoms of that element in the formula by its atomic mass.

Front

What is the atomic mass of Hydrogen (H)?

Back

The atomic mass of Hydrogen (H) is approximately 1.01 grams/mol.

Front

What is the atomic mass of Carbon (C)?

Back

The atomic mass of Carbon (C) is approximately 12.01 grams/mol.

Front

What is the atomic mass of Chlorine (Cl)?

Back

The atomic mass of Chlorine (Cl) is approximately 35.45 grams/mol.

Front

What is the total mass of CH4?

Back

The total mass of CH4 (Methane) is calculated as follows: 12.01 (C) + 4 x 1.01 (H) = 16.05 grams.

Front

How do you find the percent composition of Hydrogen in CH4?

Back

Using the formula: % comp = (Mass of H in CH4 / Total mass of CH4) x 100 = (4.04 / 16.05) x 100 = 25.2%.

Front

What is the percent composition of Hydrogen in HCl?

Back

The percent composition of Hydrogen in HCl is calculated as follows: % comp = (Mass of H / Total mass of HCl) x 100 = (1.01 / 36.46) x 100 = 2.8%.

Front

What is the percent composition of Chlorine in HCl?

Back

The percent composition of Chlorine in HCl is calculated as follows: % comp = (Mass of Cl / Total mass of HCl) x 100 = (35.45 / 36.46) x 100 = 97.2%.

Front

How many grams are in 1 mole of Carbon?

Back

1 mole of Carbon (C) contains 12.01 grams.