Which reagent is in excess?

ZnS(s) + 2HCI(aq) -> ZnCl2(aq) + H2S(g)
In a experiment performed in a fume cupboard 50.0mL of 0.10M HCI was added to 0.11g of solid zinc sulfate

1 Answer
Feb 10, 2018

Well work out the stoichiometric equivalence of zinc sulfate, and hydrochloric acid...


You gots....#ZnS(s) + 2HCl(aq) rarr ZnCl_2(aq) + H_2S(aq)#

#"Moles of HCl"=50.0*mLxx10^-3*L*mL^-1xx0.10*mol*L^-1=5.0xx10^-3*mol.#

#"Moles of zinc sulfide"=(0.11*g)/(97.47* g*mol^-1)=1.10xx10^-3*L.#

And so the hydrochloric acid is in stoichiometric excess...the reaction will be a bit smelly tho', which is why they insisted it be done in a hood.. Why so?