How many grams of chromium are needed to react with an excess of #CuSO_4# to produce 16.2 g Cu?

1 Answer
Mar 15, 2018

Answer:

its #8.775g#

Explanation:

Write down the equation for this reaction and balance it

#3CuSO_4 + 2Cr = 3Cu +Cr_2(SO_4)_3#
Calculate the amount of moles of copper. We have #16g#, and its molar mass is #64g#:

#16/64 = 0.25#

And thus the mole for chromium will be #0.17#

As the ratio suggests #2:3#

Thus #(0.25*2)/ 3 = 0.17#

Use this mole and substitute in the equation #"moles"="mass"/"molar mass"# to calculate the mass which is #0.17 * 52= 8.775g#