# chemistry

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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 -

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.

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