2. Combustion experiments are still done today Chemicals are burned in a bomb calorimeter  this provides data on the percent by mass of each element We are calculating the empirical formula: Definition: the smallest whole-number ratio between the elements in a molecule or salt

3. The Steps 1.Determine masses of each reactant. 2.Divide masses by atomic mass. 3.Divide coefficients by smallest to find ratio

4. Calculating the formula of Li x Br y 5 g of Li becomes 62.5 g of Li x Br y

5. Calculating the formula of formaldehyde C: 40% H: 7 % O: 53 %

6. Calculating the formula of aminoethanol C: 39% H: 11.5% N: 23% O: 26%

7. Your Turn!

8. Exit Ticket Your calculations lead you to determine that the mole ratio of Cs to O in cesium oxide is 2:1. What is the formula for cesium oxide? 1.CsO 2.CsO 2 3.Cs 2 O 4.Cs 2 O 2