1. Describe each step of the copper cycle with regard to the five chemical reactions. Describe the obvious physical changes that occurred and relate them to the chemical changes that copper underwent during each step. Explain why some copper compounds formed precipitates in this experiment while others remained in solution

Please see answer in explanation column

Explanation:

1.Cu(S) + 4HNO_3(aq) > Cu(NO_3)_2(aq) + 2NO_2(g) + 2H_2O(l)

2.Cu(NO_3)_2(aq) + 2Na(OH)_2(aq) > Cu(OH)_2(s) + 2NaNO3(aq)

3.Cu(OH)_2(s) {Heat}> CuO(s) + H_2O(l)

4.CuO(s) + H_2SO_4(aq) >CuSO_4(aq) + H_2O(l)

5.CuSO_4(aq) + Zn(s) > Cu(s) + ZnSO_4(aq)

B)for Step 1  

--Physical change can be seen when Reddish-Brown gas evolved and Copper dissolves and solution turns blue

- Chemival change occurs with the Formation of NO2  and Formation of Cu(NO3)2

Step 2  

Physical change can be observed with Greenish-Blue ppt   and the solution becomes colourless

chemical changes occurs with formation of Cu(OH)2 which  precipitates  and  NaNO3 solution which  is colorless

step 3  

Physical change observed when the Precipitate turns black  Chemical change occurs with Cu(OH)2 losing  water to give CuO(black)

step 4  

physical change observed when the Precipitate dissolves and solution becomes blue

Chemical change occurs with Formation of hydrated CuSO4 (blue solution)

STEP 5  

Physical change is observed with  Brown ppt and Zinc dissolves

Chemical change occurs when Solid Cu formed and Zinc replaces copper from its solution.

c) Precipitation depends on solubility of compound, from the reaction, we can find out that;

Cu(OH)2, CuO and solid Cu precipitate because they have very low solubility in water.

Cu(NO3)2 and CuSO4 do not precipitate but remain in the solutrion because they are very soluble in water.

i do not get it   at all