Question

When solutions of silver nitrate and calcium chloride are mixed, silver chloride precipitates out of solution according to the equation

2AgNO3(aq)+CaCl2(aq)?2AgCl(s)+Ca(NO3)2(aq)

Part A

What mass of silver chloride can be produced from 1.35L of a 0.166M solution of silver nitrate?

Express your answer with the appropriate units.

mass of AgCl =

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Part B

The reaction described in Part A required 3.38L of calcium chloride. What is the concentration of this calcium chloride solution?

Express your answer with the appropriate units.

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Answer 1

Stoichiometry is just the concept that you can use the coefficients in a chemical reaction to relate moles of one thing to moles of any other. Now, the molar mass (molecular weight) of a compound is what relates masses of something to moles of that thing. For things in solution, the volume and the molarity will let you get to moles of that substance. So, stoichiometry will let you determine the amounts of any other thing in an equation if you know the amount you have of one of them.

The calculations to solve any of these problems can be done one at a time, or they can often be strung together.

Part A:
1.35 L X 0.166 mol/L = 0.2241 moles AgNO3
0.2241 moles AgNO3 X (2 mol AgCl / 2 mol AgNO3) = 0.2241 mol AgCl
The molar mass of AgCl is 143.3 g/mol. So
0.2241 mol AgCl X 143.3 g / 1 mol = 32.113 grams AgCl

Part B
Since you began with 0.2241 moles of AgNO3, we'll start with that:
0.2241 mol AgNO3 X (1 mol CaCl2 / 2 mol AgNO3) = 0.112 mol CaCl2

Molarity of CaCl2 solution = 0.112 mol / 3.38 L = 0.0331 M CaCl2

Hope that all helps...