Vocabulary Percent Composition - Tells you the percentage of the mass made up by each element in the compound Empirical Formula - Gives the simplest whole number ratio of the atoms of the element Molecular Formula - Gives actual number of atoms of each element in the molecular compound

Calculating Percent Composition % of element = mass of element x 100 formula mass compound Example What is the percent composition of hydrogen and oxygen in water? Chemical Formula = H2O Formula mass = 2(1.00794g) + 15.999g = 18.01488g % of H = 2.01588g x 100 18.01488g = 11.2% % of O = 100 – 11.2 = 88.8%

Example. Find the percent composition of a compound. that contains 2 Example Find the percent composition of a compound that contains 2.30g Na, 1.60g O and 0.100g H . Total mass = 2.30g + 1.60g + 0.100g = 4.00g % of Na = 2.30g x 100 4.00g = 57.5 % % of O = 1.60g x 100 4.00g = 40.0 % % of H = 0.100g x 100 4.00g = 2.5 %

Example. A sample of an unknown compound with a. mass of 0 Example A sample of an unknown compound with a mass of 0.562g has the following percent compositions: 13.0% C, 2.2% H and 84.8% F. What is the mass of each element? Formula mass = 0.562 % of C = mass C x 100 0.562g = 13.0 % Mass C = 0.0731g % of H = mass H x 100 0.562g = 2.2 % Mass H = 0.0124g % of F = mass F x 100 0.562g = 84.8 % Mass F = 0.477g

Vocabulary Percent Composition - Tells you the percentage of the mass made up by each element in the compound Empirical Formula - Gives the simplest whole number ratio of the atoms of the element Molecular Formula - Gives actual number of atoms of each element in the molecular compound

Calculating Percent Composition % of element = mass of element x 100 formula mass compound Example What is the percent composition of hydrogen and oxygen in water? Chemical Formula = H2O Formula mass = 2(1.00794g) + 15.999g = 18.01488g % of H = 2.01588g x 100 18.01488g = 11.2% % of O = 100 – 11.2 = 88.8%

Example. Find the percent composition of a compound. that contains 2 Example Find the percent composition of a compound that contains 2.30g Na, 1.60g O and 0.100g H . Total mass = 2.30g + 1.60g + 0.100g = 4.00g % of Na = 2.30g x 100 4.00g = 57.5 % % of O = 1.60g x 100 4.00g = 40.0 % % of H = 0.100g x 100 4.00g = 2.5 %

Example. A sample of an unknown compound with a. mass of 0 Example A sample of an unknown compound with a mass of 0.562g has the following percent compositions: 13.0% C, 2.2% H and 84.8% F. What is the mass of each element? Formula mass = 0.562 % of C = mass C x 100 0.562g = 13.0 % Mass C = 0.0731g % of H = mass H x 100 0.562g = 2.2 % Mass H = 0.0124g % of F = mass F x 100 0.562g = 84.8 % Mass F = 0.477g