Question

Section : Show all your calculation steps with conversion factors formula of with units, calculator value and correct significant figures. Calculation of m shown when needed. All atomie mass of elements are up to two decimas table. products, ax sho e given in the periode 1 Following Reaction is given when zine reacts with sulfur to form Zus Zn (s) + S(s) ZnS Determine the limiting reactant when 12.72 g of Zin react with 10.90 g of sulfur(s) to produce ZnS? Show all calculation steps by using conversion factors and units. (4 pt) Srep 1: Mole of ZnS from (g) of Zn Step 2: Mole of ZnS from (g) of S Limiting reactant is: mole of ZnS produced is a) Calculate the theoretical yield (mass) of Zns formed in the above reaction. Show all steps of calculation by using conversion factors and units. (2 pts) Calculate percent yield of this reaction (2 ) b) If the actual mass of ZnS produced is 14.51 Show Formula and calculation Steps 2 In an acid-base neutralization reaction 12.51 mL of 0.160 M potassium hydroxide reacts with 12.65 mL of sulfuric acid. Calculate molarity (M) of the sulfuric acid? Show steps as 1.2.3 (4 pts) Given: 2KOH + H2SO: → K2SO4 + 2H2O Step 1: Step 2: Step 3:

Answer 1

Moles of Zn = mass of Zn / molar mass of Zn = 12.72 / 65.4 = 0.194 moles = moles of ZnS from Zn

Moles of S = mass of S / molar mass of S = 10.9 / 32 = 0.341 moles = moles of ZnS from S

We see that limiting reagent is : Zn

The excess reagent is : S

a) Theoretical yield of ZnS = moles of Zn reacted = 0.194 moles

Mass of ZnS = moles * molar mass = 0.194 * (65.4 + 32) = 18.9 g

b) percent yield = mass produced / theoretical yield * 100 = 14.51 / 18.9 * 100 = 76.77%