Chemistry Questions (3 Viewers)

[Aysce]

Quick Question

What qualitative information does the following chemical equation give you?

N2 (g) + 3H2 (g) -> 2NH3 (g)

I'm not sure what it means by "Qualitative"? Do you just explain what elements are present and how they react to form ammonia?

Thanks!

 

[someth1ng]

Re: Quick Question

Don't forget that it is equilibrium (double arrow).

Quantitative would probably refer to one mole of nitrogen gas (N2) is needed to react with three moles of hydrogen gas (H2) to produce two moles of ammonia (NH3).

.'. Four moles of gas of nitrogen and hydrogen react in a 1:3 ratio to produce two moles of gas of ammonia.

 

[Aysce]

Dot in chemical formula

I found the chemical formula of malachite (an ore of copper) in my textbook which reads: Cu(OH)2.CuCO3

Can anyone explain what the "." means?

 

[theind1996]

Re: Dot in chemical formula

It means that the ore (compound) has been hydrated.

Hydration: http://en.wikipedia.org/wiki/Hydration

 

[Aysce]

Re: Dot in chemical formula

Thanks a lot, ind

 

[theind1996]

Re: Dot in chemical formula

No worries ya animal kient!

 

[Aysce]

Chemical formula question

11.

Two non-sulfide ores of copper are malachite, Cu(OH)2.CuCO3 and azurite, Cu(OH)2.2CuCO3. Copper is extracted from these ores by first heating them to decompose the hydroxide and carbonate into oxide (the other products being water and carbon dioxide respectively). The oxide is then heated with coke (carbon) to form copper. Write chemical equations for these reactions.

In the answers it reads:

Cu(OH)2.CuCO3 (s) -> 2CuO (s) + CO2 (g) + H2O (g) for malachite.

I don't understand where 2CuO comes from? I can guess that (OH)2 and CO3 become an oxide but how do they give you 2CuO?

Thanks in advance.

 

[Aysce]

Re: Chemical formula question

Bump.

 

[Aysce]

Reaction of Copper(I) sulfide with oxygen

Q. Write an equation for the reaction of copper (I) sulfide with oxygen.

I didn't know what the products were and found them to be copper oxide and sulfur dioxide. I don't understand how the products came to be - can anyone explain please? All I know is copper reacts with oxygen to give copper oxide, but not sure about the sulfur dioxide :/

 

[someth1ng]

Re: Reaction of Copper(I) sulfide with oxygen

The sulfur in the Cu2S forms a bond with oxygen to produce SO2.

 

[Aysce]

Re: Reaction of Copper(I) sulfide with oxygen

The sulfur in the Cu2S forms a bond with oxygen to produce SO2.

Alright, thanks

 

[Aysce]

Moles calculation

Q. Consider 0.374 g aluminium chloride, AlCl3. It contains how many moles of aluminium?

 

[Aysce]

Mole calculations

Q. Consider 0.374g aluminium chloride, AlCl3. It contains how many moles of aluminium?

(Without the use of formulas such as N=m/M)

 

[Thief]

Re: Mole calculations

Why not with the formulas?

http://au.answers.yahoo.com/question/index?qid=20100605010538AAcuq9Z
http://au.answers.yahoo.com/question/index?qid=20110315054738AAAiNSu
http://community.boredofstudies.org/showthread.php?t=284543

 

[Aysce]

Re: Mole calculations

I haven't learnt the formulas yet so I assume there must be a way without them.

 

[someth1ng]

Re: Mole calculations

I haven't learnt the formulas yet so I assume there must be a way without them.

AlCl3 has a molar mass of (27+35.45x3)g/mol.

By playing around with the units...
.'. n(27+35.45x3)=0.374
n=0.374/(27+35.45x3)

It's really still using the formula but yeah, it's the only way.

 

[Thief]

Re: Mole calculations

I haven't learnt the formulas yet so I assume there must be a way without them.

Hmm didn't think there was - it's a fairly simple formula, might as well learn it now =)

 

[Aysce]

Re: Mole calculations

AlCl3 has a molar mass of (27+35.45x3)g/mol.

By playing around with the units...
.'. n(27+35.45x3)=0.374
n=0.374/(27+35.45x3)

It's really still using the formula but yeah, it's the only way.

Thanks for the confirmation about the formula and your help as usual

Hmm didn't think there was - it's a fairly simple formula, might as well learn it now =)

Yeah..

Sad thing is I spent a lot of time trying different approaches and only confused myself majorly. Oh wells. Thanks as well, Thief

 

[SpiralFlex]

Re: Mole calculations

Thanks for the confirmation about the formula and your help as usual



Yeah..

Sad thing is I spent a lot of time trying different approaches and only confused myself majorly. Oh wells. Thanks as well, Thief

This is necessary in order to understand the content.

 

[Aysce]

Re: Mole calculations

AlCl3 has a molar mass of (27+35.45x3)g/mol.

By playing around with the units...
.'. n(27+35.45x3)=0.374
n=0.374/(27+35.45x3)

It's really still using the formula but yeah, it's the only way.

I know it's a little late but I've been thinking, with your method aren't we only finding the number of moles of aluminium chloride? How are we actually finding the number of moles of aluminium?