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1. The foul smell that skunks spray is due to a number of thiols, one of which is methanethiol, CH 3 SH, which burns as follows.

CH 3 SH + 3O 2 → CO 2 + SO 2 + 2H 2 O

A sample of 10 cm 3 of methanethiol was exploded with 60 cm 3 of oxygen. What would be the final volume of the resultant mixture of gases when cooled to room temperature?

A 20 cm 3 B 30 cm 3 C 50 cm 3 D 70 cm

I don't get what we are supposed to do ...
2. Are there state symbols in the equation (aq, g, s, l)? If there were, I might be able to help.
3. (Original post by robyn2000)
Are there state symbols in the equation (aq, g, s, l)? If there were, I might be able to help.
No we haven't been given any state symbols
4. All I can tell you then is that I think you have to find the limiting reactant (which I believe to be the methanethiol). I think you then look at the stoichiometric ratio between the methanethiol and the other gas products to work out how many cm3 of them will be produced. You then must calculate the excess oxygen that is not reacted then add that on too as it asks for the resulting gaseous mixture. Sorry I couldn't be of more help!
5. The Q is ambiguous:
You will know that one mole of any gas has the same volume at same temp + pressure (22.4 litres)

So the large numbers before the formulae of gases in an equation will give proportions in volume (amount reacting on the left and amount produced on the right).

Effectively, this creature (skunk!) is fa**ing lol!!

From given eq One volume of Methanethiol + 3 vols of O2 give 1 vol CO2 and 1 vol SO2 (h2O will condense into water at room temp)

10 cm3 of methanethiol will react ith 30 cm3 of O2 so 30 cm3 of O2 will be left PLUS 10 cm3 of CO2 and 10cm3 of SO2 will be formed = TOTAL 50 cm3 (ANSWER).

HOWEVER, there is an error in the Q (is it Edexcel??) Because SO2 will probs react with the water to produce H2SO3 = sulphurous acid , so the answer could be 40 cm3, but as there is no 40 in MCQ choices, it has to be [C].

Thanks! Hope this helps.
6. (Original post by macpatelgh)
The Q is ambiguous:
You will know that one mole of any gas has the same volume at same temp + pressure (22.4 litres)

So the large numbers before the formulae of gases in an equation will give proportions in volume (amount reacting on the left and amount produced on the right).

Effectively, this creature (skunk!) is fa**ing lol!!

From given eq One volume of Methanethiol + 3 vols of O2 give 1 vol CO2 and 1 vol SO2 (h2O will condense into water at room temp)

10 cm3 of methanethiol will react ith 30 cm3 of O2 so 30 cm3 of O2 will be left PLUS 10 cm3 of CO2 and 10cm3 of SO2 will be formed = TOTAL 50 cm3 (ANSWER).

HOWEVER, there is an error in the Q (is it Edexcel??) Because SO2 will probs react with the water to produce H2SO3 = sulphurous acid , so the answer could be 40 cm3, but as there is no 40 in MCQ choices, it has to be [C].

Thanks! Hope this helps.
Thank you so much! yes it did help. It's a question from Cambridge international examinations .
Thank you once again
7. my pleasure
8. Why do 10cm3 react with only 30cm of O2? Is it because of the mole 3o2?

Updated: April 4, 2017
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