Chemistry Help..

Question

Consider the unbalanced reaction NiS2(s) + O2(g) --> NiO(s) + SO2(g)

When 11.2 g of NiS2 react with 5.43 g of O2, 4.86 g of NiO are obtained. The theoretical yield of NiO is 1._______ ,the limiting reactant is 2._______ and the percent yield is 3._______%. (Remember to use correct sig figs) 

Answer 1

First write a balanced equation:

 

2 NiS2 + 5 O2 --> 2 NiO + 4 SO2

 

to determine the theoretical yield and the limiting reactant, determine the mass of NiO produced from all of NiS2 and O2, respectively.

 

(11.2 g NiS2) x [(1 mole NiS2)/(122.81 g NiS2)] x [(2 moles NiO)/(2 moles NiS2)] x [(74.69 g NiO)/(1 mole NiO)] =

 

and

 

(5.43 g O2) x [(1 mole O2)/(32.00 g NiS2)] x [(2 moles NiO)/(5 moles O2)] x [(74.69 g NiO)/(1 mole NiO)] =

 

Whichever gives you the smallest amount of NiO should be taken as the the limiting reagent and the actual value as the theoretical yield. Finally, divide the actual yield (4.86 g NiO) by the theoretical yield and multiply by 100%.

 

I hope that helped.