Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

1)If 0.238 moles of zinc reacts with excess lead(IV) sulfate, how many grams of

ID: 540117 • Letter: 1

Question

1)If 0.238 moles of zinc reacts with excess lead(IV) sulfate, how many grams of zinc sulfate would be produced in the following reaction?

Pb(SO4) + 2Zn -> 2ZnSO4 + Pb

2)If a solution containing 55 g of mercury(II) nitrate is allowed to react completely with  a solution containing 14.334 g of sodium sulfate according to the equation below:How many grams of solid precipitate will be formed?How many grams of the reactant in excess will remain after the reaction?

3)In the following reaction, 451.4 g of lead reacts with excess oxygen forming 337.6 g of lead(II) oxide. Calculate the percent yield of the reaction.

2Pb(s)+O2(g) ------> 2pbO(s)

Explanation / Answer

1) Pb(SO4) + 2Zn -> 2ZnSO4 + Pb

1 mol Pb(SO4) = 2 mol Zn = 2 mol ZnSO4

no of mol of ZnSO4 produced = 0.238 *2/2 = 0.238 mol

Amount of ZnSO4 FORMED = 0.238* 161.44 = 38.42 g

2) Hg(NO3)2 (aq) + Na2SO4(aq) ---> HgSO4(s) + 2NaNo3(aq)

1 mol Hg(NO3)2 = 1 mol Na2SO4

No of mol of Hg(NO3)2 = W/MWT = 55/324.6 = 0.17 mol

No of mol of Na2SO4 = W/MWT = 14.334/142.04 = 0.1 mol

limiting reactant = Na2SO4

No of mol of HgSO4 formed = 0.1 mol

Amount of precipitate = 0.1*296.653

                       = 29.66 g

amount of excess Hg(NO3)2 = (0.17-0.1)*324.6 = 22.722 g

3) 2Pb(s)+O2(g) ------> 2pbO(s)

no of mole of Pb = w/mwt = 451.4/207.2 = 2.18 mol

theoretica yield of PbO = 2.18*223.2 = 486.576 g

percent yield = practical yield/theoretical yield*100

               = 337.6/486.576*100

                = 69.4%