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What's Chico Time Precious?
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#1
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can someone give me advantages and disadvantages of liquid/gaseous fuels?

environmental factors relating to ethane, methane, octane....

also: i still dont understand thermal stability

kinetic stability is where if a reaction is exothermic, products are stable and reactants unstable, is trhis right???
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What's Chico Time Precious?
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damn, ah well, i've looked and looked, hope i'll be ok
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cobra
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Try filling and tank full of hydrogen then bursting it near a naked flame
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What's Chico Time Precious?
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(Original post by cobra01977)
Try filling and tank full of hydrogen then bursting it near a naked flame
i would love to laugh but i'm too tired and hoping for a USEFUL reply
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cobra
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That is kind of useful in disguise
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cobra
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#6
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weight - energy density, ie energy per unit of mass
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MadNatSci
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(Original post by Absolution)
can someone give me advantages and disadvantages of liquid/gaseous fuels?

environmental factors relating to ethane, methane, octane....

also: i still dont understand thermal stability

kinetic stability is where if a reaction is exothermic, products are stable and reactants unstable, is trhis right???

OK. Gaseous fuels take up less space and are lighter, but liquid fuels are easier to handle (gases can easily escape etc). Also liquid fuels generally have to become a gas before they'll burn - when petrol burns it's the vapour and not the liquid - gases are already gaseous so will burn instantly. Liquids are not massively safer, but they are safer. As for environmental things - I can't remember the exact values but I think you have to look at the energy given off per mole compared to the amount of carbon dioxide released per mole combusted, and I'm pretty sure the bigger alkanes - like octane - are less environmentally friendly than ethane/methane according to this.

Stability I'll come back to because I haven't studied it in ages and I don't want to give you a wrong answer! So I'll check the stuff first. I'm pretty sure the above is right.
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What's Chico Time Precious?
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(Original post by MadNatSci)
OK. Gaseous fuels take up less space and are lighter, but liquid fuels are easier to handle (gases can easily escape etc). Also liquid fuels generally have to become a gas before they'll burn - when petrol burns it's the vapour and not the liquid - gases are already gaseous so will burn instantly. Liquids are not massively safer, but they are safer. As for environmental things - I can't remember the exact values but I think you have to look at the energy given off per mole compared to the amount of carbon dioxide released per mole combusted, and I'm pretty sure the bigger alkanes - like octane - are less environmentally friendly than ethane/methane according to this.

Stability I'll come back to because I haven't studied it in ages and I don't want to give you a wrong answer! So I'll check the stuff first. I'm pretty sure the above is right.
thx very much, luckily it didnt come up in the exam so i was ok.
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MadNatSci
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(Original post by Absolution)
thx very much, luckily it didnt come up in the exam so i was ok.

OK, that's good - for some reason I couldn't find the stability stuff anywhere; I'd need to go back to my notes and they're all at home Damn my crappy memory!!
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Ralfskini
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(Original post by MadNatSci)
OK. Gaseous fuels take up less space and are lighter, but liquid fuels are easier to handle (gases can easily escape etc). Also liquid fuels generally have to become a gas before they'll burn - when petrol burns it's the vapour and not the liquid - gases are already gaseous so will burn instantly. Liquids are not massively safer, but they are safer. As for environmental things - I can't remember the exact values but I think you have to look at the energy given off per mole compared to the amount of carbon dioxide released per mole combusted, and I'm pretty sure the bigger alkanes - like octane - are less environmentally friendly than ethane/methane according to this.

Stability I'll come back to because I haven't studied it in ages and I don't want to give you a wrong answer! So I'll check the stuff first. I'm pretty sure the above is right.


I would have thought gases take up more space than the same mass of liquid. Also, apparently it's impossible for a man to lift a 1kg of Hydrogen gas at 2000 psi.
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-=G® TM=-
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You all forgot 1 important factor! Gaseous fuels are very expensive to transport and need special containers which are expensive!!
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matouwah
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#12
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it came up in the edexcell chem unit 2 exam.....why is it better to use hydrogen than propanol considering environemental factors...
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MadNatSci
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(Original post by Ralfskini)
I would have thought gases take up more space than the same mass of liquid. Also, apparently it's impossible for a man to lift a 1kg of Hydrogen gas at 2000 psi.

You can compress the gases and they're smaller molecules... I'm sure that was one of the reasons we had when I was doing it anyway Dunno about the hydrogen thing. Anyway, it was my birthday and I was marginally (!) pissed, so gimme a break
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GH
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(Original post by MadNatSci)
You can compress the gases and they're smaller molecules... I'm sure that was one of the reasons we had when I was doing it anyway Dunno about the hydrogen thing. Anyway, it was my birthday and I was marginally (!) pissed, so gimme a break
WOW! Your birthday.

Happy bday mate.
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MadNatSci
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(Original post by 2776)
WOW! Your birthday.

Happy bday mate.

Thanks I feel so old...
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crana
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(Original post by MadNatSci)
You can compress the gases and they're smaller molecules... I'm sure that was one of the reasons we had when I was doing it anyway Dunno about the hydrogen thing. Anyway, it was my birthday and I was marginally (!) pissed, so gimme a break
sorry to be dense, but when you compress the gases don't they eventually liquify anyway?

Rosie

Ps, HAPPY BIRTHDA Y
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cobra
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Happy birthday
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MadNatSci
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#18
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Thanks everyone... yeah, they will compress into liquids, I was trying to find a way out of the hole I'd dug myself into
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joicey
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#19
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i aint done a-level chem in 6 yrs but im sure kenetic stability is where a reaction is enodthermic the product is stable and the reactant isnt stable
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