Zinc metal reacts with copper(II) ion in solution to produce zinc ion and copper metal, as follows.Zn(s) + Cu2+(aq) ? Zn2+(aq) + Cu(s)You add 7.675 grams of Zn metal to 27.0 mL of 0.270 M CuSO4·5H2O and allow the reaction to proceed until the blue color of the solution is gone. You note that copper metal is plating out on the zinc pellets. How many moles of Zn have you added to the flask? (Unit is mol).How many moles of Cu2+ ion are in the solution? (Unit is mol).How many moles of Zn will have reacted with the Cu2+ when the reaction is complete? (Unit is mol).How many moles of Zn will remain unreacted? (Unit is mol).What mass of Zn will remain unreacted? (Unit is g).How many moles of Cu metal will be produced? (Unit is mol).What mass of Cu metal will be produced? (Unit is g).When the metal pellets are removed, dried, and weighed, what should be their total mass?
Molar mass of zinc is 65.40 g/mol, of copper 63.546 (you can find that in a periodic table of elements). Amount of zinc equals n=m/M; 7.675 g/65.40 g/mol = 0.117 mol. Molar concentration (c=n/V) of CuSO4?5H2O is 0.270 mol/L, volume equals 27.0 mL = 0.027 L. Amount of CuSO4?5H2O equals 0.27 mol/L X 0.027 L = 0.000729 mol. Each mol of CuSO4?5H2O gives one mol of Cu2+ ions (CuSO4→Cu2+ + SO42-), so amount of Cu2+ ions in a solution is 0.000729 mol. One mol of Zn reacts with one mol of Cu2+ (Zn + Cu2+→Zn2+ + Cu), therefore 0.000729 mol of Zn reacted. 0.117mol (starting amount)-0.000729 mol (reacted amount) = 0.116 mol of Zn remained in a solution. That means 7.586 g of zinc remained (0.116 mol X 65.38 g/mol). One mol of Zn reacts with one mol of Cu2+, therefore 0.000729 mol of Cu is produced, which is 0.046 g. Total mass of pellets (copper coated zinc) is (starting mass of zinc – mass of reacted zinc) + mass of produced copper: 7.586g Zn + 0.046 g Cu = 7.63 g.
