Tuesday, March 8, 2011

#stoichiometry calculations involving particles - moles - mass# by:mandy

STOY-KEE-AHM-EH-TREE is a study of amounts of substances that are involved in reactions! lots of calculations involved. So, think Math!
what are the steps to calculationg the amounts od substances in a reaction?
1. write equation                                                
3."road map"                                                               
now, lets try an example:
step 1:
Mg + HCl --> MgCl2 + H2
since this reaction is not balanced yet, we'd have to preform step 2:
Mg + 2HCl --> MgCl2 + H2
step 3:
Note that when we are making a "road map", substances CANNOT be diretly convert from grams of one compound to grams od another. Instead, we have to go through moles :)
grams (x) <--> moles (x) <--> moles (y) <--> grams (y)
final step *4:
6.0g H2 x 1 mol H2/2.02g H2 x 1 mol Mg/ 1 mol H2 x 24.3g Mg/ 1 mol Mg = 72.2g Mg
YAY! good job! that was the step by step calculation.

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