Stoichiometry Calculations

(Moles, particles, atoms)

Ex:  How many grams of Ca are produced if there are 4.24 moles of HBr?

       1).  Balance the eq'n:    2Ca+2HBr--->2CaBr+1H2 
       2). Next make a road map:  4.24 mol HBr---> ?grams Ca
       3). Now do the calculation: 4.24 mol HBr x 1 mol Ca x 80.2g Ca  = 85g Ca.
                                                                        2 mol HBr   2 mol Ca


Try some practice problems:
1) How many moles of HCl are needed to produce .76 g of CaCl?
2) How many grams of Ca are needed to produce  1 molecule of H?
3) How many atoms of H will be formed when 3.42 moles of Cl are formed?
4) How many grams of CaCl are needed to form 8.19 moles of HCl?

Check out this link: http://www.youtube.com/watch?v=jVtP9VSrdGw&feature=related
If catchy songs help you study, then this link will do the trick.

-Lauren