HSC Chemistry Question Thread

[RuiAce]

Hi am i correct in thinking that we only need to know either Zeiglar Natta polymerisation or free radical polymerisation in depth (and just have a simple understanding of the other process? Not both?
TIA

Actually I think the process is the exact same. The only difference is that the former uses the Ziegler-Natta catalyst, whereas the latter uses a peroxide initiator.

It's activation -> propagation -> termination in all cases.

[onepunchboy]

How do i do q7 ? P.s the value of k is 1.7 x 10^-10

Thanksss

[lha]

DO we write esterification reactions with an equilibrium or forward arrow?

[massive]

do we always write aqueous for the state for salts??

[massive]

guys how do you do neutralisation reactions with oxides?? :S

[onepunchboy]

Can someone explain question 8 and 9? Thank you , much appreciated!

[RuiAce]

DO we write esterification reactions with an equilibrium or forward arrow?

Esterification is reversible so equilibrium. In fact the equilibrium lies heavily to the left - hardly any products are formed.

do we always write aqueous for the state for salts??

If they precipitate no, otherwise yes

guys how do you do neutralisation reactions with oxides?? :S

You lost me on this one. Example please

[RuiAce]

(Image removed from quote.)

How do i do q7 ? P.s the value of k is 1.7 x 10^-10

Thanksss

Interesting question

[RuiAce]

(Image removed from quote.)

Can someone explain question 8 and 9? Thank you , much appreciated!

For Q9 A and C are obviously wrong because one is a weak base and the other is strong

B is also wrong because they have different molar masses, so if n is the same, then because n=m/MM we have different masses

Similar discussions on why D is the correct answer can be found in posts #1170 and #1171

[lha]

WHen we talk about ethanol from renewable sources, do we talk about sugar cane or cellulose?

[RuiAce]

WHen we talk about ethanol from renewable sources, do we talk about sugar cane or cellulose?

Wouldn't you briefly mention both, because cellulose is derived from sugar cane?

[lha]

Wouldn't you briefly mention both, because cellulose is derived from sugar cane?

So how would i say it?

[RuiAce]

So how would i say it?

Give a brief mention to what sugar cane is and why it's renewable, and then just explain that you can get cellulose from it to which you can get ethanol from cellulose.

Think about it logically. How would you structure it so that it makes sense to someone.

Everyone writes differently; I can't tell you "how" to write an extended response, or bits and pieces of it.

[lha]

Give a brief mention to what sugar cane is and why it's renewable, and then just explain that you can get cellulose from it to which you can get ethanol from cellulose.

Think about it logically. How would you structure it so that it makes sense to someone.

Everyone writes differently; I can't tell you "how" to write an extended response, or bits and pieces of it.

I say that sucrose from sugar cane is hydrolysed to form glucose, then glucose ia fermented to get ethanol. Where does the cellulose come in?

[wesadora]

I say that sucrose from sugar cane is hydrolysed to form glucose, then glucose ia fermented to get ethanol. Where does the cellulose come in?

Cellulose is a constituent of sugar cane. Sugar cane = biomass. ALL biomass contains cellulose! Just say sugar cane is a source of cellulose.