Chem questions help. (1 Viewer)

[Bigfatnacho]

Just some questions I need help in.

1. Calculate the mass of copper present in the 3.90g of Copper (II) Oxide.

2. Explain how the work of Gay-Lussac and Avogadro led to an understanding of the structure of the molecules of these gases

3.Write two Half equations and an overall ionic equation to represent this reaction

4.Calculate the mass of zinc required to produce 7.5g of hydrogen.


I'm sorry If I'm asking too many questions but I'm just struggling in those atm. If you can't tell me the exact answer can you atleast teach me how to do them or give me a link that teaches you how to do them?

cheers

 

[Kurosaki]

2Cu +O2--> 2CuO
So looking at the mole ratios- 2 moles of copper will give 2 moles of copper oxide.
calculate the amount of moles in 3.90g of CuO.
that is the number of moles of copper.
convert to mass.

for 2- what gases?

for number 4, you use the equation Zn + 2H+ --> Zn2+ + H2

here, just convert mass of hydrogen into moles, use mole ratios and work out moles of zinc, then convert to mass

 

[Bigfatnacho]

2Cu +O2--> 2CuO
So looking at the mole ratios- 2 moles of copper will give 2 moles of copper oxide.
calculate the amount of moles in 3.90g of CuO.
that is the number of moles of copper.
convert to mass.

for 2- what gases?

for number 4, you use the equation Zn + 2H+ --> Zn2+ + H2

here, just convert mass of hydrogen into moles, use mole ratios and work out moles of zinc, then convert to mass

Thanks heaps man and dw about 2 I understood it.

 

[Bigfatnacho]

Also can you give me tips on how to solve these type of questions?