VCE Chemistry Question Thread

[HopefulLawStudent]

lol. Idk.

My answer doesn't make sense, I know that much. I just don't know how to do the Q. Just gonna ask my tutor on Saturday.

PS: Whenever you find out the answer, please share? Would love to know.

[Elizawei]

FOUND THE ANSWERS!
ugh she made a typo..... it's 120 ml instead of 100 ml, thats why it didn't work 


This is her working out ^^

[HasibA]

FOUND THE ANSWERS!
ugh she made a typo..... it's 120 ml instead of 100 ml, thats why it didn't work 
(Image removed from quote.)

This is her working out ^^

i remember being given the exact same question with a similar typo, and i was like 'wtf' until my teacher realized he made a typo xD
I swear these type of questions always pop up on my sacs and there's always some type of misprint/error etc. -.-

anyways, do we have to know why TetraMethylSilane is so stable and has  a chemical shift of zero or so? questions in my book are popping up about this.....

[Swagadaktal]

FOUND THE ANSWERS!
ugh she made a typo..... it's 120 ml instead of 100 ml, thats why it didn't work 
(Image removed from quote.)

This is her working out ^^

where did the 480 mL of h2o come from :O

[Elizawei]

where did the 480 mL of h2o come from :O

120mL + 360mL apparently.... not sure why she added them though

anyways, do we have to know why TetraMethylSilane is so stable and has  a chemical shift of zero or so? questions in my book are popping up about this.....

and yes, we do need to know. It's because it only has one carbon environment and one hydrogen environment due to it's symmetry so the all four carbon atoms in a tetramethylsilane molecule are equivalent.

[Swagadaktal]

120mL + 360mL apparently.... not sure why she added them though

and yes, we do need to know. It's because it only has one carbon environment and one hydrogen environment due to it's symmetry so the all four carbon atoms in a tetramethylsilane molecule are equivalent.

but aint that 360 mL for the CO2
I'm like 73% sure your teacher was cooked when writing this question

[jyce]

Oh also got another quick question:

Identify one method that could be used to verify that the substance produced is pure propyl propanoate.
How do we verify that something is an ester???

_{Have a sac tomorrow pls help} 

Thanks in advance

Thin-layer chromatography.

[Elizawei]

but aint that 360 mL for the CO2
I'm like 73% sure your teacher was cooked when writing this question

HAHHAAH COOKED. Yup 
Maybe she made some mistake... it's so weird ... hmm I'll ask her in my next lesson

[Swagadaktal]

HAHHAAH COOKED. Yup 
Maybe she made some mistake... it's so weird ... hmm I'll ask her in my next lesson

please do
that question caused far more frustration than it warranted. It's not that complicated but coz of the wrong numbers I was completely baffled

[knightrider]

How would you do these questions?

[Swagadaktal]

It's just the mass of the thing in the q... coz you know how there's isotopes, sometimes you get Cl 35 and Cl 37 which have 2 separate masses. Therefore for a) you would just add up the masses using the mass of Cl35, for the second question it's just 37 + 37 + 12 + 2, for the first it's 12 + 2 + 37 + 35.5 (if i remember correctly) [i think, if im wrong someone correct mepls ]

[Elizawei]

How would you do these questions?

Isn't it just 86 and 88

[Elizawei]

Haha you beat me to it Swagadaktal 
But yeah, figuring out the parent molecule is just finding the molar mass of the stuff pretty much. That's why on a mass spec it's very useful for determining the molar mass of the sample

[knightrider]

It's just the mass of the thing in the q... coz you know how there's isotopes, sometimes you get Cl 35 and Cl 37 which have 2 separate masses. Therefore for a) you would just add up the masses using the mass of Cl35, for the second question it's just 37 + 37 + 12 + 2, for the first it's 12 + 2 + 37 + 35.5 (if i remember correctly) [i think, if im wrong someone correct mepls ]

Thanks Swagadaktal  just a little thing for your second one it should be 12 + 2 + 37 + 35(not 35.5)=86 

Isn't it just 86 and 88

Haha you beat me to it Swagadaktal 
But yeah, figuring out the parent molecule is just finding the molar mass of the stuff pretty much. That's why on a mass spec it's very useful for determining the molar mass of the sample

yep you're right Elizawei Thankyou 

[Swagadaktal]

Thanks Swagadaktal  just a little thing for your second one it should be 12 + 2 + 37 + 35(not 35.5)=86 

yep you're right Elizawei Thankyou 

OH YEAH soz I didn't read it properly soz not sure why my mind went in that direction. yes. i need sleep