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March 29, 2024, 03:32:53 am

Author Topic: VCE Chemistry Question Thread  (Read 2313260 times)  Share 

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Jason12

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Re: VCE Chemistry Question Thread
« Reply #780 on: April 27, 2014, 04:20:05 pm »
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how to do part b of the question. I'm trying to grasp the n+1 rule but I don't really know how to use it properly
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Blondie21

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Re: VCE Chemistry Question Thread
« Reply #781 on: April 28, 2014, 11:41:38 am »
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What is the name of this compound?

I always thought that the -OH group needs to be prioritised but apparently it is pronan-2-ol
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nhmn0301

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Re: VCE Chemistry Question Thread
« Reply #782 on: April 28, 2014, 11:51:23 am »
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how to do part b of the question. I'm trying to grasp the n+1 rule but I don't really know how to use it properly
So your CH3 is next to a CH2, the number of hydrogen on its neighboring chemical environment will determine its number of split on the NMR,hence, 2+1=3 splits.
What is the name of this compound?

I always thought that the -OH group needs to be prioritised but apparently it is pronan-2-ol
You got a CH3 there, so there is 3 carbon in the compound, the -OH is bonded to the second one.
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Blondie21

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Re: VCE Chemistry Question Thread
« Reply #783 on: April 28, 2014, 01:13:03 pm »
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Sooo even though there is a -OH group, it is not included in the 'mother chain'?
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Yacoubb

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Re: VCE Chemistry Question Thread
« Reply #784 on: April 28, 2014, 04:18:39 pm »
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Sooo even though there is a -OH group, it is not included in the 'mother chain'?

The hydroxyl group does not need to be at carbon 1. You must identify the longest chain, and the functional group must be present in this mother chain. So, you have CH3CHOHCH3, which is 2-propanol.

Hope this helped :)

Jawnle

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Re: VCE Chemistry Question Thread
« Reply #785 on: April 28, 2014, 06:38:12 pm »
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Is it possible for C2H6 + OH- to produce ethanol? Or would I need to make it into a chloroalkane beforehand

The question is "Using the appropriate catalysts and other reaction conditions, which of the following set of reactants will produce ethanol as a product?
I) C2H6 +OH-
II) C2H4 + H2O
III) CH3CH2COOCH3 + H20

A) I only
B) II only
C) II and III only
D) I, II and III

For II I got ethanol, for III I got methanol, so it shouldn't be C or D. Since I'm certain that II produces ethanol, I'm guessing the answer is B?

What do you guys think??
« Last Edit: April 28, 2014, 06:40:31 pm by Jawnle »

katiesaliba

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Re: VCE Chemistry Question Thread
« Reply #786 on: April 28, 2014, 07:30:41 pm »
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In gas chromatography, will more polar samples have a low retention time because the liquid hydrocarbon stationary phase is non-polar? 
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lzxnl

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Re: VCE Chemistry Question Thread
« Reply #787 on: April 28, 2014, 08:22:30 pm »
+1
Is it possible for C2H6 + OH- to produce ethanol? Or would I need to make it into a chloroalkane beforehand

The question is "Using the appropriate catalysts and other reaction conditions, which of the following set of reactants will produce ethanol as a product?
I) C2H6 +OH-
II) C2H4 + H2O
III) CH3CH2COOCH3 + H20

A) I only
B) II only
C) II and III only
D) I, II and III

For II I got ethanol, for III I got methanol, so it shouldn't be C or D. Since I'm certain that II produces ethanol, I'm guessing the answer is B?

What do you guys think??

Hydroxide isn't reactive enough to cleave a C-H bond. The reason why chlorine reacts with methane under UV light is because the chlorine molecule absorbs the UV light and dissociates to form individual Cl atoms. These only have 7 valence electrons and are thus VERY reactive. It takes something of that reactivity to react with a C-H bond.

From my own knowledge, only the hydration of ethene, in your list, produces ethanol, so you'd be correct.
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Robert123

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Re: VCE Chemistry Question Thread
« Reply #788 on: April 28, 2014, 09:08:01 pm »
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How much do we need to know about galactose for chemistry?

lzxnl

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Re: VCE Chemistry Question Thread
« Reply #789 on: April 28, 2014, 10:18:05 pm »
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In gas chromatography, will more polar samples have a low retention time because the liquid hydrocarbon stationary phase is non-polar?

It depends on what stationary phase you ACTUALLY use. You could, for all we know, use some polar liquid that is still a liquid at 200 degrees.

How much do we need to know about galactose for chemistry?

Nothing at all I think. All I know is that it's an isomer of glucose and it was enough for me. The exam never asked anything on it.
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Yacoubb

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Re: VCE Chemistry Question Thread
« Reply #790 on: April 28, 2014, 10:19:46 pm »
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Do we need to know/state the state of phosphoric acid catalyst in hydration or the state of H2SO4 or any catalysts really in organic chemical pathways.

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Re: VCE Chemistry Question Thread
« Reply #791 on: April 29, 2014, 05:25:15 pm »
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Why does oxygen not absorb IR radiation?
« Last Edit: April 29, 2014, 05:40:01 pm by Marco Reus »
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Snorlax

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Re: VCE Chemistry Question Thread
« Reply #792 on: April 29, 2014, 06:09:14 pm »
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Why does oxygen not absorb IR radiation?
Because it's a diatomic molecule. Similar with N2.
This means they're not polarised
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PsychoT

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Re: VCE Chemistry Question Thread
« Reply #793 on: April 29, 2014, 06:30:18 pm »
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Why are Cyclohexane/Cyclohexene good organic solvents?
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lzxnl

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Re: VCE Chemistry Question Thread
« Reply #794 on: April 29, 2014, 07:18:32 pm »
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Why does oxygen not absorb IR radiation?

It's not just because it's diatomic; it's homonuclear as well, which means any bond stretch wouldn't change its overall dipole moment. As a result, IR radiation is not absorbed.

Why are Cyclohexane/Cyclohexene good organic solvents?

They're non-polar much like other organic compounds, so there is little energy cost (if at all) for any organic solute to dissolve.
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