TrueTears question thread

[TrueTears]

Also what's a hydrophobic side group? (Just met this term in a NEAP test have no idea what it means.)

[hyperblade01]

Also what's a hydrophobic side group? (Just met this term in a NEAP test have no idea what it means.)

Hydrophobic is a term used alot in biology for 'water hating'

So, as water is polar, a hydrophobic side group is non-polar?

[TrueTears]

Also what's a hydrophobic side group? (Just met this term in a NEAP test have no idea what it means.)

Hydrophobic is a term used alot in biology for 'water hating'

So, as water is polar, a hydrophobic side group is non-polar?

Ahh cool, thanks!

[TrueTears]

3. I think you should name it hydrolysis, as that is the "specific" name of the reaction. Most alkenes will undergo addition reactions anyway, so it would be better if you label the actual name of the reaction.


remember that the type of reaction is addition, and the specific name of the reaction is hydrolysis.

Small technicality:

There is a difference between 'hydrolysis' and 'hydration'

In when water reacts in an addition reaction with a double bond, it is a 'hydration' reaction.

A + H2O --> B

In terms of organic chemistry, hydrolysis usually involve splitting of a larger molecule when reacting with water

A + H2O --> B + C

(and same goes for dehydration [A --> B + H2O] and condensation [A + B --> C + H2O])
These are not the most technically correct definitions, as hydrolysis doesn't necessarily split molecules in inorganic, physical and electrochemistry, but it will do

Heinemann still calls it hydrolysis for an addition reaction. Do we need to know about hydration?

I asked our teacher and she said for vce, hydrolysis would be enough. Yes Heinemann calls it hydrolysis but in the lisa chem test the answers only had addition. I mean it is an addition reaction, but isn't hydrolysis more accurate?











Also can all hydrocarbons undergo combustion reactions?

[lacoste]

I think its better and safe to place the two terms; hyrdolysis and addition reaction if approriate, in regards to the specific question.

All hydrocarbons undergo combustion given that there is surplus oxygen or else its incomplete combustion

[TrueTears]

Thanks lacoste.

also another question, what are the monomers (2 of them) which make up this polymer.



thanks!

[chem-nerd]

ethene and but-1-ene

[TrueTears]

ethene and but-1-ene

Ah cool thought so, thanks heaps chem-nerd!

[TrueTears]

and one last question

1L hydrocarbon undergoes combustion with 6.5L of oxygen at the same temperature. What is this hydrocarbon?

Thanks

[chem-nerd]

can assume V is equal to n when T and P constant

=>  2CyHx + 13O₂ -> 2yCO₂ + xH₂O  (doubled coefficients to make whole no's -> easier)

=> number of O's = 26 = 4y + x

=> assuming it's an alkane then x = 2y + 2

=> 26 = 6y + 2, thus y = 4

=> hydrocarbon could be C₄H₁₀ (can check by writing a balanced combustion equation for butane)



(if you assumed it was an alkene then x = 2y, then 26 = 6y which doesn't give a whole number)

[TrueTears]

Thank you once again chem-nerd!

[Mao]

ethene and but-1-ene

Would that form the regular -(CH)₄- arrangement? Would it have to be catalysed by something special?

Could it be but-1-ene and cyclopropane?

[chem-nerd]

hhmmm
cyclopropane's bonds have similar reactivity to ethene's double bond but it breaks down to form propene, which wouldn't give the same polymer

even though it looks like a regular -(CH₄)- arrangement the but-1-ene monomer has already changed its orientation in that one segment

for VCE land, I'd stick with the ethene and but-1-ene option
in reality, there probably is a way to create this regular arrangement

[TrueTears]

A quickie question:

When you add a sodium onto the carboxy group for aspirin to make it more soluble is it or COO-Na? Teacher says its COO-Na but heinemann says its

Thanks.

[ed_saifa]

It's the Na+