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

Stoichiometry???

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                                                

2.balance

3."road map"                                                               

4.calculations!

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.