Replying to Massive Karma for any Chem majors willing to help me

I cant figure out this question on my General Chemistry Homework
Please Help

1. To a 150 mL beaker were added 0.510 g of solid copper powder and 2.5 mL of a 15 M aqueous solution of nitric acid. Brown fumes were evolved, and 25 mL of water was then added to the blue solution formed. To the aqueous solution was added 3.010 g of solid sodium carbonate in small portions. Only after all of the excess hydrogen ion in the aqueous solution was consumed by reaction with added carbonate ion did carbonate ion precipitate copper (II) ion as copper (II) carbonate. The solid copper (II) carbonate was isolated by vacuum filtration and dried; 0.920 g of copper (II) carbonate was collected. The net ionic equations for the reactions which occurred are shown below.

Cu(s) + 4H+(aq) + 2NO3-(aq) → Cu2+(aq) + 2NO2(g) + 2H2O(l)
2H+(aq) + CO32-(aq) → H2O(l) + CO2(g)
Cu2+(aq) + CO32-(aq) → CuCO3(s)

a. Calculate the percent yield of copper (II) carbonate.
b. Could copper turnings (i.e. thin, short ribbon of solid copper) be used instead of copper powder? Justify your choice.
c. Would using 3.010 g of solid sodium carbonate decahydrate instead of 3.010 g of sodium carbonate, with all other amounts of reagents being used kept the same as above, have any effect? Justify your decision, being as specific as possible.