Posted by Anonymous on Monday, September 30, 2013 at 4:37pm.
A mixture of NaCl and NaBr has a mass of 2.04g and is found to contain 0.70g of Na. What is the mass of NaBr in the mixture?

chemistry  DrBob222, Monday, September 30, 2013 at 4:50pm
A problem with two unknowns and two equations. Solve simultaneously.
Let x = mass NaCl
and y = mass NaBr

x + y = 2.04
x(atomic mass Na/molar mass NaCl) + y(atomic mass Na/molar mass NaBr) = 0.70

Substitute the numbers to get this.
x + y = 2.04
x*(23/58.4) + y*(23/102.9) = 0.70

Solve these two equations. You want y for mass NaBr. Post your work if you get stuck.