chapter9_apjk

4 c. of flour 3 c. of sugar 3 eggs 1 tsp. of vanilla 2 sticks of butter 1 tsp. of salt 8 c. of chocolate chips
 * Chapter 9 Stoichiometry ** [[image:http://bhs.smuhsd.org/science-dept/marcan/apchemistry/016.jpg width="175" height="141" align="right"]]
 * Getting Started:**
 * //__These following ingredients at the top make 4 dozens of cookies__//**

If you have.. 20 c. of flour 15 c. of sugar 15 eggs 7 tsp. of vanilla 4 sticks of butter 5 tsp. of vanilla 30 c. chocolate chips
 * //__You can only make 8 dozens of cookies because of butter. The butter is the limiting reactant.__//**

1) Get a balanced equation 2) Figure out the multiplication factor 3) Find out number of mol of what you need 4) Convert mol to g using molar mass (If must)
 * How to do stoichiometry: **

to the following chemical equation? 2Na + Cl2 --> 2NaCl 1) Find the molar mass of the compound 2) Find the percentage of each element's mass
 * Example**: How many moles of chlorine gas (Cl2) would react with 5 moles of sodium (Na) according
 * Answer:** 2.5 mol Cl2
 * Finding percent composition:[[image:http://www.kcl.ac.uk/kis/schools/life_sciences/health/pharmacy/resgrps/mcrg1/MedChemGp01/images/Fecp20.jpg width="256" height="189" align="right"]] **

1) Find the molar mass of the compound: The molar mass of CO2 is 44. C = 12, O = 16 2) Find the percentage of each element's mass. C = 12/44, O = 32/44
 * Example:** What is the percent of carbon and oxygen in CO2
 * Answer:** 27.27% Carbon, 72.73% Oxygen

** Determing empirical formulas: ** 1) Find the number of moles of each element 2) Find the ratio of moles of each element (divide by smallest) 3) Apply the ratio to the formula

1) Find the number of moles of each element: 0.29 mol S, 0.435 mol O 2) Find the ratio of moles of each element (divide by smallest): 0.29 mol S / 0.435 mol O = 1: 1.5 ratio However since you can't have half of a mol, you have to double the ratios to get the whole number --> 2:3 ratio 3) Apply the ratio to the formula: S, O = S2O3
 * Example:** 0.29 mol S, 0.435 mol O. Find the empirical formula for S and O.
 * Answer:** S2O3 (2:3 ratio)**

Finding molecular formulas: ** 1) Find the empirical formula 2) Find the mass of empirical formula 3) Divide molecular mass (given) by the mass of the empirical formula 4) Multiply empirical formula by anser from step 3

Molecular mass of the empirical formula: S2O3 1) Find the empirical formula: S2O3 2) Find the mass of empirical formula: 32 * 2 + 16 * 3 = 112 3) Divide molecular mass (given) by the mass of the empirical formual: 224 / 112= 2 S2O3 * 2 = S4O6
 * Example:** Given molecular mass: 224 g/mol. Find the molecular formula for S and O.
 * Answer:** S4O6

Made by. James Kim and Adam Polinak Pictures from... [] [] 