Before 1982 the US Mint cast penny coins from a copper and zinc mixture. If a 1980 penny weighs 3.051g and contains 0.153g zinc, what is the percent of copper in the coins?
94.99%
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3.051 g = mass Cu + Zn
-0.153 g = mass Zn from the problem.
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2.898 g Cu
%Cu = (2.898/3.051)*100 = ??
3.051 g Cu and Zn -0.153 g Zn=2.898 g Cu
After that: 2.898 g Cu/3.051 g Cu+Zn=0.94985 x 100%=94.99%
To find the percent of copper in the 1980 penny, we need to determine the weight of copper in the coin and then calculate its percentage.
First, let's find the weight of copper in the coin. We know that the total weight of the penny is 3.051g and it contains 0.153g of zinc. Therefore, we can subtract the weight of zinc from the total weight to find the weight of copper.
Weight of copper = Total weight - Weight of zinc
Weight of copper = 3.051g - 0.153g
Weight of copper = 2.898g
Now, let's calculate the percentage of copper in the coin. To do this, we divide the weight of copper by the total weight of the coin and multiply by 100.
Percent of copper = (Weight of copper / Total weight) * 100
Percent of copper = (2.898g / 3.051g) * 100
Percent of copper ≈ 94.99%
Therefore, the 1980 penny contains approximately 94.99% copper.