Chapter 3 - Chemical Reactions and Reaction Stoichiometry - Exercises - Page 115: 3.45c

CH2O

Since we have values in percents, we can assume a 100g basis. Then we have 40g C, 6.7g of H and 53.3 g of O. Then we convert these to moles; C is 12g/mol so 40g is 3.33 mole H is 1g/mol so 6.7g is 6.7 mole O is 16g/mol so 53.3g is 3.33 mole Then we divide by the smallest number, which is 3.33 3.33/3.33 = 1 6.7/3.33 = 2 3.33/3.33 =1 The ratio is 1:2:1 so we have CH2O