Question

An alloy is a mixture of metals. Suppose that a certain alloy is made by mixing 50 grams of an alloy that contains 52% copper with 78 grams of pure copper.a). How many grams are in the resulting mixture? __grams.b). What percentage of the resulting mixture is copper? ___%

Answer 1

Answer:

a) 128 grams

b) 81.25%

Explanation:

a) The mixture will be between the alloy and the pure copper, so the mass will be the sum of the mass of the compounds:

m = 50 + 78 = 128 g

b) In the alloy, 52% is copper, so to know the mass of copper in the alloy, we must multiply the total mass by 52% (which is 0.52)

0.52x50 = 26 g of copper

The total mass of copper in the mixture is 26 + 78 = 104 g

So, the percentual of copper is the mass of copper divided by the total mass

104/128 = 0.8125

Multiplying by 100%, to have the result in percentage

0.8125x100% = 81.25%