Problem: Common brass is a copper and zinc alloy containing 37.0% zinc by mass and having a density of 8.48 g/cm3. A fitting composed of common brass has a total volume of 120.5 cm3 .How many atoms of zinc does the fitting contain?

FREE Expert Solution

We’re being asked to determine the number of atoms of zinc in a fitting containing 37.0 % by mass Zn


We know that the fitting is a common brass alloy composed of copper, Cu and Zinc, Zn.


And to do that we're going to do the following steps:


Step 1: Solve for mass of the common brass fitting (solution) using the volume and 

density of the fitting.


volume solution (density) → mass solution


Step 2:  Solve for mass of Zinc using the mass percent formula shown below:


mass percent=mass componenttotal mass×100


Since we are dealing with an alloy (solid solution), we can rewrite the equation as:


% mass=mass solutemass solution×100


Step 3: Solve for moles of Zn in fitting and # of atoms of Zn using Avogadro's number


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Problem Details

Common brass is a copper and zinc alloy containing 37.0% zinc by mass and having a density of 8.48 g/cm3. A fitting composed of common brass has a total volume of 120.5 cm3 .

How many atoms of zinc does the fitting contain?