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=__Other information: Converting__=

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When you need to convert things such as grams of a given substance to grams of an unknown substance, or grams of a given to moles, you need to do a process called stoichiometry.

__Example Problem__
2H20 ---> 2H2 + O2

For this example we will convert 5 grams of H2O into grams of O2

In order to finish you conversion there are a number of steps you must follow

1. First you Start with your given

5g H2O

2. You then convert your grams into moles by multiplying your given by 1 mole of your given over the molar mass of your given

5g H2O x 1 mol H2O / 18g H2O

3. The next step is to repeat this process but instead of putting mols over grams, you use the molar ratio from the balanced equation. The molar ratio is number of moles of the unknown, or in this case O2, over the number of moles of given, in this case H2O, from your balanced equation.

5g H2O x 1 mol H2O / 18g H2O x 1 mol O2 / 2 mols H20

4. Your next and last step is to find the grams of unknown, in this case O2. You do this by putting the molar mass of the unknown over 1 mol of unknown.

5g H2O x 1 mol H2O / 18g H2O x 1 mol O2 / 2 mols H2O x 32g O2 / 1 mol O2

5. lastly you look at the whole equation and multiply the numbers on the top row and divide by the numbers on the bottom row.

5g H2O x 1 mol H2O / 18g H2O x 1 mol O2 / 2 mols H2O x 32g O2 / 1 mol O2 = 4.4g O2

Now you have finished your stoich problem

If you have noticed the pattern that you put the same units on the bottom as the units on the previous top in the equation, then your probably wondering why that is. The reason for this is because as you do your equation you cancel those units out. This is because it allows for you to come up with your desired units.

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