ppm help (1 Viewer)

[crammy90]

2007 22a
the sulphur content in diesel fuel.
i cant understand the answers
i can see ppm for that year is 50ppm
i dont understand why they do:
"sulphur content in tank fuel = 50/1,000,000 x 60 = 3.0g"
and with this part what equation are they using to do this i.e. how do they know the molar ratio
" since 1 mol S produces 1 mole SO2
V(SO2) = 3/32.07(FM S) x 24.79L = 2.3L"
ive been at it for 15mins....

 

[The-Exiled]

Is your question how do they know that 1 mol of sulfur makes one mol of SO2?

S(s) + O2(g) --> SO2(g)

1 + 1 --> 1 (mols)

And because there is 3/32.07 mols of sulfur there must be 3/32.07 mols of SO2

Then because it is defined at 25 degrees and 100Kpa then it must be multiplied by 24.79 to get the volume of gas present


I hope that helped, haha

 

[crammy90]

yeh see i know that equation but i didnt know how they could assume that equation when the sulphur is part of the diesel. Like wouldnt the deisel have to be apart of the reaction aswell?
and the other part of the question was why do they do the 50/1,000,000 and then times by the 60kg.
thanks for trying tho

 

[The-Exiled]

Oh i see, yeah the diesel is. But i think your meant to assume that it is burnt in sufficient oxygen so no matter what your always gonna have the sulfur being completely burnt (along with the diesel).

well they have 50ppm

So the 50/1,000,000 part is to get the percentage of sulfur. Then they just get the amount of sulfur out of 60kg of the diesel by multiplying it by the percentage. Which is 3g.

 

[crammy90]

so you have to assume that there arent 2,000,000 parts in the deisell.
like what i am interpreting the question as is that there are 50 parts of S in 1,000,000 diesel parts. I dont understand how you can know how many parts are in the deisel. Like although there may be 50 ppm of S in diesel there may be 2,000,000 deisel parts
i confused myself lol
OK lol
so you have 60KG of deisel. Thats 60 x 1000(g) x 1000(mg) = 60,000,000mg
now: in 1,000,000 parts there are 5

i.e. 1,000,000 : 5
​

therefore:60,000,000: 5 (60) = 300
so in that 60KG there are 300 parts of S
so: 1,000,000 : 60,000,000
5 : 300

Dont know where i was going with that aha
OKAY i read ur post again. So the 50ppm is in the ratio to 1,000,000parts of the diesel. So i think i understand. So if they realistically had lets say 250,000 parts of deisel and 1.25 parts were S, they make it into a univeral ratio???
so they multiplied each by 4:
i.e. 1.25 x 4 and 250,000 x 4
to get 5 : 1,000,000
yeh???
aha
thanks for helping me i think i sorta understand now
i didnt realise the ppm were in ratio to eachother like if there are the 5 parts of S thats a ratio in comparison to 1,000,000 parts diesel
aha

 

[The-Exiled]

so you have 60KG of deisel. Thats 60 x 1000(g) x 1000(mg) = 60,000,000mg

now: in 1,000,000 parts there are 5

i.e. 1,000,000 : 5

​

therefore:60,000,000: 5 (60) = 300
so in that 60KG there are 300 parts of S
so: 1,000,000 : 60,000,000
5 : 300

What you did there is right!

 

[crammy90]

aha well thats good to know
is there any point of doin that


actually i know what i was doing lol
basically:
50ppm = 50mg/L
so:
50mg : xmg
1Lggggggg60L

50mg x 60L = xmg
1L

3000mg/L = xmg
1Lgggggggggggggggggg(divide by L)

3000mg = xmg xmg = 3000mg so there are 3000mg/60L = 3g/60L
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