Calculating Change in [Cl-] in 2AgNO3(aq) + CuCL2(aq) Reaction

[Complex_]

Homework Statement

2AgNO3(aq) + CuCL2(aq) --> 2AgCl(s) + Cu(NO3)2(aq)

The concentration of Ag(NO3)2(aq) at t = 30s is .42 mol/L. At t = 60.0 its concentration is .28 mol/L. What is the change in [CL^-] during this time?

Homework Equations

The Attempt at a Solution

Not really sure even how to begin.

 

[Bystander]

t = 30s is .42 mol/L.

t = 60.0 its concentration is .28 mol/L.

What could change the concentration of silver nitrate?

What is the change in [CL^-]

Got any ideas?

2AgNO3(aq) + CuCL2(aq) --> 2AgCl(s) + Cu(NO3)2(aq)

This help?