Chemistry Examination Discussion

[achre]

I'd get out of bed and draw a prettier picture but i don't want to
Does this work for the isomer question?

[rany]

guys would for that accuracy question, would i be right by stating the voltage supplied by the DC supply as a factor that can affect accuracy?

[Edward21]

I'd get out of bed and draw a prettier picture but i don't want to
Does this work for the isomer question?

I'd pay for that, that's really smart!!

[Stick]

Damnit, I put CH3CH2CH2COOH. I thought the data book suggested that the CH2 groups would be the same. Unless I missed something?

[eddybaha]

i got ii and iii for situations where back titration would  be better than forward titration. not sure how something being volatile makes back titration better

[beastly101]

i got ii and iii for situations where back titration would  be better than forward titration. not sure how something being volatile makes back titration better

Titrations generate some form of heat though which would evaporate the volatile component, hence why a back titration is needed.

[random_person]

I got methylpropanoic acid - same as Edward. Did we have to name this molecule?

[brightsky]

case in point: NH3. ammonia is very volatile, and if we wanted to measure the concentration of ammonia in say a sample of cloudy ammonia, we really wouldn't want all the ammonia escaping. so we convert NH3 into NH4+ by adding a tonne of acid like HCl, just to make sure that NH3 doesn't get lost.

[Stick]

Is there anything wrong with CH3CH2CH2COOH for that isomer question? I can't think of a reason as to why it's wrong.

[brightsky]

the CH2 are in different environments. the one closer to the COOH would be more deshielded. stuff up to two carbon atoms away have an influence on the degree of shielding.

[beastly101]

Is there anything wrong with CH3CH2CH2COOH for that isomer question? I can't think of a reason as to why it's wrong.

Isn't that four carbon environments seeing as the CH2's are attached to different groups?
ie CH3 - CH2 and CH2-COOH, so that would be 4 environments rather than 3?

Not sure though, originally I had that but changed it haha

[achre]

Is there anything wrong with CH3CH2CH2COOH for that isomer question? I can't think of a reason as to why it's wrong.

Four carbon enviros, cos the COOH will cause a cascade of deshielding across the chain. But now that I think it over, I think we had to come up with an alternate molecule that matched with all other spec data, which just sounds way too hard for such an easy exam.
Goddamn I wish I had a copy in front of me right now.

[Stick]

Urgh... The data booklet let me down, because it only says RCH2R, so I thought the environments could still be considered the same? Any chance of the mark? XD

[Mr Keshy]

the CH2 are in different environments. the one closer to the COOH would be more deshielded. stuff up to two carbon atoms away have an influence on the degree of shielding.

I didn't even think of that..

Urgh... The data booklet let me down, because it only says RCH2R, so I thought the environments could still be considered the same? Any chance of the mark? XD

Fingers crossed haha

[beastly101]

Urgh... The data booklet let me down, because it only says RCH2R, so I thought the environments could still be considered the same? Any chance of the mark? XD

Don't stress mate, 119/120 is still good lol