Question

Powdered zinc and sulfur react in an extremely rapid, exothermic reaction. The zinc sulfide that is formed can be used in the phosphor coating on the inside of a television tube.Zn(s) + S(s) → ZnS(s)A 6.00 g sample of Zn is allowed to react with 3.35 g of S. Determine the excess reagent and how many grams of it will remain after the reaction.Select one:a.Zinc, 0.407 gb.Sulfur, 0.407 gc.Zinc, 8.94 gd.Sulfur, 8.94 g

Answer 1

`\text{ Zn}_{(\text{s\rparen}}\text{ + S}_{(\text{s\rparen}}\text{ }\rightarrow\text{ ZnS}_{(\text{s\rparen}}\text{ }`
`\text{ 6.00 g Zn }*\frac{1\text{ mol Zn}}{65.4\text{ g Zn}}=\text{ 0.0917 mol Z}`
`3.35\text{ g S }*\frac{1\text{ mol S}}{32.07\text{ g S}}=0.1045\text{ mol S}`

Since the reaction is 1:1, the limiting reactant is Zn and the excess reactant is S.

Mass in excess of S

`\text{ mass = 32.07 g/mol * \lparen}\frac{3.35\text{ g}}{32.07\text{ g/mol}}-\frac{6\text{ g}}{65.4\text{ g/mol}}\text{\rparen = 0.4078 g S}`

So the answer is option b sulfur 0.407 g