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Problem: Iron(II) sulfide reacts with hydrochloric acid according to the reaction:FeS(s) + 2 HCl(aq) → FeCl2(s) + H2S(g)A reaction mixture initially contains 0.226 mol FeS and 0.656 mol HCl.Once the reaction has occurred as completely as possible, what amount (in moles) of the excess reactant remains?

FREE Expert Solution

We are asked to calculate the amount (in moles) of the excess reactant. 


FeS(s) + 2 HCl(aq) → FeCl2(s) + H2S(g)


Calculate the mole FeCl2 based on both reactants: 


0.226 mol FeS × 1 molFeCl21 mol FeS  = 0.226 mol FeCl20.656 mol HCl × 1 molFeCl22 mol HCl  = 0.328 molFeCl2

Since FeS produced less product, it is limiting. 


Calculate HCl used.  

0.226 mol FeS × 2 molHCl1 mol FeS  = 0.452 mol HCl


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Problem Details

Iron(II) sulfide reacts with hydrochloric acid according to the reaction:

FeS(s) + 2 HCl(aq FeCl2(s) + H2S(g)

A reaction mixture initially contains 0.226 mol FeS and 0.656 mol HCl.

Once the reaction has occurred as completely as possible, what amount (in moles) of the excess reactant remains?

Frequently Asked Questions

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Limiting Reagent concept. If you need more Limiting Reagent practice, you can also practice Limiting Reagent practice problems.