Find the molar mass and % composition of zinc acetate. [Zn(CH3COO)2] ... Molar mass = 183.4 g
5.7% Zn, 26.2% C, 3.3% H, 34.9% O
Finding the Empirical Formula from Experimental Data
1) Get the number of grams of each element
2) For each element, convert grams to moles
3) Divide each number of moles by the smallest number of moles
4) Use the ratio to write the formula
1) % --> g
2) g --> mol
3) mol / mol
A compound is found to be 45.5% Y and 54.5% C. Find its empirical formula.
A compound of ruthenium and sulfur is 67.7% Ru. Find its empirical formula.
A sample of a compound is found to be 5.88 g silver, 0.56 g phosphorous, 1.16 g oxygen.
Find its empirical formula.
Molecular Formula from Empirical Formula
Divide the molecular mass of the compound by the molar mass of the empirical formula.
The molecular formula will be a multiple of the empirical formula.
Example: Given - Empirical formula is CH
molecular mass of compound is 78 g/mol. Determine the molar mass of the empirical formula CH = 13 g/mol
Solve: 78 / 13 = 6
Therefore, the molecular formula is 6 (CH) =
(pg 238-243). 9.7 PECENT COMPOSITION (pg 238-239)
Objective: To calculate the percent composition of a compound given its
9.8 EMPIRICAL FORMULA (pg 239-241)
Objective: To calculate the empirical formula of a compound given
its mass composition. Objective: To calculate the empirical formula of a compound given its
9.9 MOLECULAR FORMULA (pg 241-243)
Objective: To calculate the molecular formula for a compound given its
empirical formula and molar mass.