The provided text is a solution to a chemistry question about the reactions of ammonia with copper(II) oxide and lead(II) oxide. What was the original question?

Here are the answers to your questions:

3. • a) Write an equation for the reaction that occurs in the combustion tube. (1mk)

     $$2\text{NH}_{3}(\text{g}) + 3\text{CuO}(\text{s}) \longrightarrow 3\text{Cu}(\text{s}) + \text{N}_{2}(\text{g}) + 3\text{H}_{2}\text{O}(\text{l})$$

   • b) State and explain the observations that were made in the combustion tube. (3mks) The black solid (copper(II) oxide) turned into a brown/pink solid (copper metal). This is because ammonia reduced the copper(II) oxide to copper metal.

   • c) Name gas Y. (1mk)

     • Nitrogen

   • d) (i) State any changes in observations that would be made if lead (II) oxide was used instead of copper (II) oxide. (2mks) The yellow solid (lead(II) oxide) would turn into a grey/silver solid (lead metal).

   • d) (ii) Write an equation for the reaction between ammonia gas and lead (II) oxide. (1mk)

     $$3\text{PbO}(\text{s}) + 2\text{NH}_{3}(\text{g}) \longrightarrow 3\text{Pb}(\text{s}) + \text{N}_{2}(\text{g}) + 3\text{H}_{2}\text{O}(\text{l})$$

   • d) (iii) What property of ammonia is shown by the reaction in the combustion tube? (1mk)

     • Reducing property (Ammonia acts as a reducing agent).

   • e) State two uses of ammonia. (2mks)

     • i) Manufacture of fertilizers (e.g., ammonium sulfate, urea).
     • ii) Manufacture of nitric acid. (Alternatively: used as a refrigerant or in the manufacture of explosives).
4. • a) Other than their location in the atom, name two other differences between an electron and a proton. (2mks)
     • i) Charge: Protons are positively charged ($+1$), while electrons are negatively charged ($-1$).
     • ii) Mass: Protons have a significant mass (approximately 1 atomic mass unit), while electrons have a negligible mass (approximately $\frac{1}{1836}$ of a proton's mass).