M&M Lab a.k.a. Empirical and Molecular Formulas Lab Purpose: To calculate the percent composition of each “element” and determine the empirical and molecular formulas of the “compound.” Introduction: A compound has been chemically decomposed into its component elements. Each M&M represents one mole of a particular type of “element.” Each color represents a different “element” and has its own symbol and atomic mass, given in the chart below. M&M’s Color Red Orange Yellow Green Blue Brown Symbol R Or Y G Bl Bn Atomic Mass (g/mol) 1 2 3 4 5 6 You must show all work to receive credit! Procedure: 1. Count each color of “element” and fill out the chart below. Each M&M represents one mole of the “element.” “Element” Number of Moles Present Total Mass of “Element” Present (g) Number of “Atoms” Present R Or Y G Bl Bn Empirical and Molecular Formulas Lab Page 1 of 3 2. Write the empirical formula and calculate the empirical mass of your “compound.” Empirical Formula: __________________________ Empirical Mass: ______________ g/mol 3. Calculate the percent composition for each “element” in your “compound.” “Element” % Composition R Or Y G Bl Bn Show work here: 4. Another lab found, through special tests, that the molecular mass is 3 times that of the empirical mass. Write the molecular formula of your “compound” and calculate its molecular mass. Molecular Formula: __________________________ Molecular Mass: ______________ g/mol 5. Another compound was found to be 3.3% Or, 25.0% Y, 13.3% G, and 58.3% Bl. Determine the empirical formula and empirical mass. Empirical and Molecular Formulas Lab Page 2 of 3 6. Another compound was found to be 5.5% R, 21.8% Y, 18.2% Bl and 54.5% Bn. Determine the empirical formula, the empirical mass and the molecular formula if the molecular mass is 275 g/mol. Empirical and Molecular Formulas Lab Page 3 of 3