For a chemistry lab, you used 2 ounces of calcium sulfate, 2.5 pounds of copper, and 1/4 lb of nickel. what was the combined weight of your materials?

What you want to do is convert all your amounts to ounces. 
There are 16 oz in a pound. 
So for the copper do this equation.
2.5*16=40
This means there are 40 oz of copper.
Do the same with nickel.
0.25*16=4 oz
This means you have 4 oz of nickel. 
Combine the numbers:
2+40+4=46
Your answer will be 46 oz of material. 
Hope this helps!

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