What is the maximum number of mols of copper (III) sulfide that can be formed when 8.0 mols of copper reacts with 9.0 mols of sulfur?

1 Answer
Costas C.
Mar 20, 2016

You have to find the reaction, balance it and then compare the mole ratios.
Answer is:

#5,bar(33)g#

Explanation:

The chemical reaction is:

#4Cu+3S_2->2Cu_2S_3#

So from the left part of the equation, once can say:

For every 4 moles of copper, 3 moles of sulfur is needed.
For every 8 moles of copper, #x# moles of sulfur are needed.
For every #y# moles of copper, 9 moles of sulfur are needed.

#x=(3*8)/4=6# moles of sulfur We have 9, which is enough

#y=(4*9)/3=12# moles of copper We have 8, which is not enough

So finally, 8 moles of sulfur will react. The reaction will become:

#4Cu+3S_2->2Cu_2S_3#

#zCu+8S_2->wCu_2S_3#

#z=4*8/3=32/3#

#w=2*8/3=16/3#

#32/3Cu+8S_2->16/3Cu_2S_3#

So the maximum number moles that can be formed are:

#16/3=5,bar(33)g#

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