Posted by
**hayat** on
.

0.872g sample containing only NaBr and KBr gives 1.052g AgBr. what's the % of each salt?

This is the type of problem that cannot be answered without other information.

**I think you have made a typo in your problem I worked through it and I get negative numbers for the mass of NaBr and KBr. Of course that can not be. Perhaps the mass AgBr produced is 1.502 and not 1.052; that is, perhaps you transposed those numbers. Check it out.**

The problem is set up this way but you will need to substitute the correct values. I have used **1.502g for mass AgBr produced**.

You have two equations and two unknowns.

Let Y = grams KBr.

Let Z = grams NaBr.

Note: AgBr, KBr, and NaBr below stand for molar mass of those materials.

=======================

eqn 1 is Y + Z = 0.872

eqn 2 is Y(AgBr/KBr) + Z(AgBr/NaBr)=1.502

Solve for Y and Z which is grams of each.

Then determine % by

%KBr = (massKBr/1.502)*100 and

%NaBr=(mass NaBr/1.502)*100.

Post your work if you get stuck.