4.4 NOTES Percent Composition

Composition of Materials Percent composition the mass of a material found in a compound % composition = mass of element in formula x 100 total mass of formula  

Used to describe how much material is present in a particular ore or item Post-1982 pennies with a mass of 2.500 g contain 2.4375 g zinc and 0.0625 g copper. What is the percent composition of each element? Zinc:   Copper:

A Roosevelt dime, the US 10-cent coin since 1946, has a mass of 2 A Roosevelt dime, the US 10-cent coin since 1946, has a mass of 2.268 g. It is composed of 8.33% nickel and 91.67% copper. Calculate the mass of each metal present.

C.8 Moles and Percent Composition When choosing which mineral to use to extract copper, you need to consider the percent composition. Some Copper-Containing Minerals What is the percentage of copper in chalcocite? Two factors to consider when choosing a mineral: how much of the mineral is in the ore how much of the metal is in the mineral Common Name Formula Bornite Cu5FeS4 Chalcocite Cu2S Chalcopyrite CuFeS2 Malachite Cu2CO3(OH)2

Use the copper-containing minerals table to answer the following Use the copper-containing minerals table to answer the following. You may assume that each mineral is present at the same concentration in an ore and that copper metal can be extracted from a given mass of any ore at the same cost. Mass of Part/Mass of Whole Compound x 100 Calculate the percent copper in chalcocite. Cu2S  67%     

63% Calculate the percent copper in bornite. Cu5FeS4  63%    Calculate the percent copper in malachite. Cu2CO3(OH)2 57.5%

Which of these minerals – chalcocite, bormite or malachite – could be mined most profitably?