OCR A Chemistry F322 Chains, Energy and Resources Thu 19 Jan 2012

Original post by splendidsun

nooope

but i think the general definition for biofuels is fuels that have been made from recently living materials like plants

ahhh right okay, ive noted that thanks :smile:

Reply 103

Original post by zainahmed

Im struggling with halogenoalkanes what does evryone know about them?

They are alkanes with atleast one hydrogen on the carbon chain substituted with a halogen (in order of decreasing electronegativity: Cl, Br, I)

Due to the difference in electronegativity between the carbon and halogen, a dipole is established across the bond which deems it prone to attack by nucleophilic substitution. This explains why halogenoalkanes can take part in hydrolysis reactions, the OH ions being the nucleophiles due to the presence of a lone pair.

Reply 104

Original post by dee11

why does 1-Iodopropane hydrolyed faster than 1-bromopropane?

starting off pretty easy :biggrin:

Weaker bond, less energy required to break

Reply 105

Original post by zainahmed

the amount of radiation it can absord i think its infared radiation? correct me if am wrong

and its relative concentration in the atmosphere

the amount a gas has and effect is measured by its GWP global warming potential score

yeahh, pretty much. Its the gases ability to absorb IR and the concentraion of the gas in the atmosphere like you said

Reply 106

Original post by splendidsun

Weaker bond, less energy required to break

yeah your right, but i think you'd have to mention weaker Bond enthalpy between C-I somewhere too to get the 2 marks

you've got the idea though

Reply 107

Do the molar quantities effect the atom economy?

Reply 108

Original post by dee11

yeah your right, but i think you'd have to mention weaker Bond enthalpy between C-I somewhere too to get the 2 marks

you've got the idea though

yh, true that

what are the uses of crude oil fractions?

Reply 109

zainahmed

Original post by nffc-b

Do the molar quantities effect the atom economy?

accidently pressed negative rating sorry

and yeh i think it does cos it involves molecular mass not sure??

Reply 110

What is the environmental damage caused by

i) Nitrogen Oxide
ii) Nitrogen Dioxide

Reply 111

2 reasons why enthalpy changes of cumbustion determined experimentally may not match the standard enthalpy values?

Reply 112

Original post by zainahmed

accidently pressed negative rating sorry

and yeh i think it does cos it involves molecular mass not sure??

Haha its cool bro, and I think it does aswell, but in all the past papers its always been just 1mole of each when asking for the atom economy so I dunno

Reply 113

zainahmed

anyone care to explain what halogens have go to do with cfcs

Reply 114

Original post by dee11

2 reasons why enthalpy changes of cumbustion determined experimentally may not match the standard enthalpy values?

Heat energy released to surroundings

Incomplete combustion may have taken place

(+ standard conditions may not have been met)

Reply 115

Original post by dee11

2 reasons why enthalpy changes of cumbustion determined experimentally may not match the standard enthalpy values?

Loss of heat to the surroundings
Incomplete combustion
May not be standard conditions

Reply 116

Original post by splendidsun

yh, true that

what are the uses of crude oil fractions?

you mean like fractional distilaton?

Reply 117

Original post by dee11

you mean like fractional distilaton?

Reply 118