# Weight %

1. Oct 4, 2006

### lorka150

the equation is CaCl2 + 2AgNO3 --> AgCl Ca(NO2)2
my mix is CaCl2 and other stuff that does not react with AgNO3.
0.2918 g of mix gives 0.4462g of AgCl, what is the percent of CaCl2 in the mix?
Molar masses are CaCL2 110.98g/mol and AgCl 143.32 g/mol.
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I am not sure if this is how to do it, however...
moles of the AgCl is 0.4462/143.32 = 0.003113 mol

moles of CaCl2 is 0.4462-0.2918 = 0.1544 grams of CaCl2, then 0.1544/110.98 = 0.001391 mols of CaCl2

i don't know if that's right so far, or where to go from there. i know i need to use the ratios somewhere but ack!

2. Oct 4, 2006

### Stevedye56

the equation is CaCl2 + 2AgNO3 --> AgCl Ca(NO2)2

Is this plus the calcium nitrite or a raised dot meaning its part of one unit?
(AgCl Ca(NO2)2)?

3. Oct 4, 2006

### lorka150

sorry, there should be a plus.

CaCl2 + 2AgNO3 --> AgCl + Ca(NO2)2

thanks for pointing it out!

4. Oct 4, 2006

### Staff: Mentor

Assuming you have correctly calculated that

contains

answer should be slightly over 50%...

Trick is, 0.1544 is wrong. No idea what you are trying to find subtracting masses of different compounds. This is simple stoichiometric problem, easily solved using ratios (or dimensional analysis).