Mass to Mass Conversions

Today we learned about Mass to Mass problems and converting between them. It was actually really fun!

Example: Questions:

How many grams of O2 are produced from the decomposition of 3.0 g of Potassium Chlorate?


This question gives us grams, but we must change it to grams of another element. First we must write a balanced Chemical equation:


2KClO3 ----> 2K +  Cl2 + 3O2


Than we take what we are given, which is 3.0 grams. Change 3.0 grams into moles, than find what you need over what you have, than with the moles you are given, find grams!


3.0 g x 1 mol  = 0.024 mol x 3 O2 (what you need)
             122.6 g                        2KClO3 (what you have)


= .036 mol x 32.0 g
                      1 mol
= 1.2 g


There you have it!

Let's try one more because this stuff is easy eh?


Question: Determine the mass of lithium hydroxide produced when 0.38 g of lithium nitride reacts with water according to the following equation:

Li3N +3H2O ---> NH3+ 3LiOH

0.38 g x 1 mol = 0.011 mol x 3(LiOH) = 0.033 g x 23.9 g 

                                                         34.7 g                         1mol                            1 mol

=0.78mol

Nice! Okay carry on with your lives

Post by ren ren again