The chemical formula for chalcopyrite, #"CuFeS"_2# indicates that each mole of the compound contains one mole of copper.
The following represents the method that will be used to determine how many kg of #"CuFeS"_2# must be mined to obtain #"325g Cu"#.
#color(red)("mass Cu"##rarr##color(blue)("mole Cu"##rarr##color(green)("mol CuFeS"_2"##rarr##color(magenta)("mass CuFeS"_2"#
#color(purple)("Molar Masses"#
The first thing you need to do is determine the molar masses for copper and chalcopyrite.
The molar mass of #"CuFeS"_2# is #"183.511 g/mol"#
https://www.ncbi.nlm.nih.gov/pccompound?term=CuFeS2
The molar mass of #"Cu"# is #"63.546 g/mol"# (periodic table)
#color(red)("Mass Cu"# to #color(blue)("Moles Cu"#
Divide the given mass of #"Cu"# by its molar mass by multiplying by the inverse of the molar mass.
#325color(red)cancel(color(black)("g Cu"))xx(1"mol Cu")/(63.546color(red)cancel(color(black)("g Cu")))="5.11 mol Cu"#
#color(blue)("Moles Cu"# to #color(green)("Moles CuFeS"_2"#
Multiply moles #"Cu"# by the mole ratio between #"Cu"# and #"CuFeS"_2"# with #"CuFeS"_2"# in the numerator.
#5.11color(red)cancel(color(black)("mol Cu"))xx(1"mol CuFeS"_2)/(1color(red)cancel(color(black)("mol Cu")))="5.11 mol CuFeS"_2"#
#color(green)("Moles CuFeS"_2"# to #color(magenta)("Mass CuFeS"_2"#
#5.11color(red)cancel(color(black)("mol CuFeS"_2))xx(183.511"g CuFeS"_2)/(1color(red)cancel(color(black)("mol CuFeS"_2)))="938 g CuFeS"_2"# rounded to three sig figs
#color(orange)("Convert mass in grams to kilograms".#
#938color(red)cancel(color(black)("g")) "CuFeS"_2xx(1"kg")/(1000color(red)cancel(color(black)("g")))="0.938 kg CuFeS"_2"#
