1.  Mass of crucible + lid = 29.809g  Mass of crucible + lid + Mg = 29.935g  Mass of crucible + lid + magnesium oxide = 30.004g

2.  What is the molecular formula for this compound ?  What is the empirical formula ?

3.  Calculate the amount (in moles) of each element  Find the simplest whole number ratio between these elements  2.476 g of an oxide of copper is found to contain 2.199 g of copper. Determine its empirical formula.

4.  The % composition of organic compounds are found by burning a known mass in excess oxygen and then finding the masses of carbon dioxide and water formed.  2.80 g of an organic compound, containing only carbon and hydrogen forms 8.80 g of carbon dioxide and 3.60 g of water when it undergoes complete combustion. Determine its empirical formula.

5.  Consider vitamin C, a compound that contains carbon, hydrogen and oxygen only. On combustion of 1.00 g vitamin C, 1.50 g CO2 and 0.408 g H2O are produced. Determine the empirical formula of vitamin C.