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Chemistry Question, I don't understand..

Carbon reacts with oxygen to form the compound carbon dioxide:
C(s) + O2(g) - CO2 (g)

If 0.60g of carbon is burnt in excess oxygen, calculate the mass of carbon dioxide produced.

How do I work this out? Thanks in advance :smile:

Reply 1

usycool1

Original post by Mazthemelon

Well, what have you tried? :smile:

Calculating the number of moles of carbon burnt may be a good start.

Reply 2

melonthemango

Original post by usycool1

Well, what have you tried? :smile:

Calculating the number of moles of carbon burnt may be a good start.

ah, right.. work out moles:

no. of moles= mass of substance/ molar mass

= 0.6/12
=0.05 moles

I think.. ><

Reply 3

usycool1

Original post by Mazthemelon

ah, right.. work out moles:

no. of moles= mass of substance/ molar mass

= 0.6/12
=0.05 moles

I think.. ><

Good, now how many moles of CO2 would there be (look at the balanced equation)?

Reply 4

melonthemango

Original post by usycool1

Good, now how many moles of CO2 would there be (look at the balanced equation)?

hmm.. would it be one? (because there's one mole of carbon and one of oxygen?) I'm not too sure

Reply 5

usycool1

Original post by Mazthemelon

hmm.. would it be one? (because there's one mole of carbon and one of oxygen?) I'm not too sure

Nope

You have the right sort of idea though. :smile:

The equation shows that for every one mole of carbon burned, one mole of CO2 would form - the mole ratio is 1:1. As you have 0.05 moles of carbon, the number of moles of carbon dioxide would also be the same (0.05).

So you have the number of moles of CO2, you can work out it's Mr quickly and you can use Mass = Mr x Moles to work out the mass. :smile:

Reply 6

Plantagenet Crown

Original post by Mazthemelon

hmm.. would it be one? (because there's one mole of carbon and one of oxygen?) I'm not too sure

The ratio is 1:1

So 1C gives 1CO₂

Therefore 0.05C would give?

Reply 7

melonthemango

Original post by Plantagenet Crown

The ratio is 1:1

So 1C gives 1CO₂

Therefore 0.05C would give?

Ohh I see! 0.05C would give 20CO2, right? ^_^

1C= 1CO2

(Divide both sides by 0.05)

0.05= 20CO2

Reply 8

mattcandy3

The ratio is 1:1 0.05 mol of C would give 0.05 mol of C02, im sure you can do the rest :smile:

Reply 9

Plantagenet Crown

Original post by Mazthemelon

Ohh I see! 0.05C would give 20CO2, right? ^_^

1C= 1CO2

(Divide both sides by 0.05)

0.05= 20CO2

Huh?! You don't divide the grams. The ratio is 1:1 so 0.05 mols of Carbon would give 0.05 mols of CO₂

Reply 10

melonthemango

Original post by Plantagenet Crown

Huh?! You don't divide the grams. The ratio is 1:1 so 0.05 mols of Carbon would give 0.05 mols of CO₂

Sorry! >< My chemistry teacher had her fair share of drilling basic chemistry into my head. I'll get there.. eventually. Thank you for your help :smile:

Reply 11

germas369

Since you have 0.05mol of CO2 (as mentioned previously), to work out the Mass of CO2 produced, you must use the following equation: mass=number of moles*Relative Molecular mass. The Mr of CO2 is 12(Carbon)+(2*16(Oxygen))=44
Seeing as you now have the Mr(44) of CO2 all you have to do is multiply that by 0.05mol as the ratio 1:1. Which gives you the total mass of CO2 produced 2.2g :smile:

I hope I didnt confuse you more because I got stuck on this for a little bit too but I read back pages 33-38 in AS Chemistry AQA text book and everything came back :smile:

Good luck!