1. The same at first: CuSO4(aq) + 2NH4OH ===> Cu(OH)2(s) + (NH4)2SO4(aq) CuSO4(aq) + NaOH(aq) ===> Cu(OH)2(s) + Na2SO4(aq) If you add excess NH3, you get a soluble compound again, something that does not happen with NaOH: Cu(OH)2(s) + 2NH4OH ===> Cu(NH3)2++(aq) + 2OH-(aq)

Sulfates and hydroxides are both soluble in water. 2 NaOH + CuSO4 ---> Na2SO4 + Cu(OH)2

2. A) Because one of the products is a gas, CO2 and this escapes. By Le Chatelier, the system responds by producing more, and this escapes and so on. Hence the equilibrium goes to the right.

Le Chatelier: If a restraraint is applied to a system, the system tries to overcome that restraint .. or in everday language, if you do something eg let CO2 escape, the reaction tries to oppose it.

B)-

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4. Balanced redox reaction: 2CrO42- + 2H+ Cr2O72- + H2O

If the pH gets too low, then there will be excess H+.According to LeChatlier's Principle, that will drive the equilibrium forward to yield the more reduced dichromate ion.

Conversely, if the pH is too high, then there is a deficiency of aqueous H+, therefore the equilibrium will be driven tothe left to yield the more oxidized chromate ion.

The reaction can be tracked based on absorbances of the solution which vary depending on the ion-complexes in solution. Essentially intensity of solution color will vary with concentration of acid insolution.

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6. The temperature would go down because by introducing hydrochloric acid, Chloride ions are introduced into the equilibrium. By LeChatlier's principle of equilibrium, the equilibrium will shift towards the product side. Since the reaction is an endothermic reaction more heat will be absorbed as more products are created; hence, the temperature will drop.