Predictions for Chemistry 2014 HSC? (2 Viewers)

Queenroot

I complete the Squar3
Joined
Sep 11, 2011
Messages
7,487
Location
My bathtub
Gender
Female
HSC
N/A
Too generic for me :p Try this one pulled straight from the syllabus dotpoints that I think a lot of people will lose marks:

Describe the structure of cellulose (3)
If they don't know the answer to this then they haven't studied properly. It is one key application of condensation polymers.

Clearly you haven't watched pocohontas
 

mreditor16

Well-Known Member
Joined
Apr 4, 2014
Messages
3,169
Gender
Male
HSC
2014
lol I'm laughing hard at you guys. let's get back on topic, before the mods ban seventh again as a scapegoat for our derailing.... :D
 
Joined
Feb 16, 2014
Messages
2,258
Gender
Male
HSC
2014
Too generic for me :p Try this one pulled straight from the syllabus dotpoints that I think a lot of people will lose marks:

Describe the structure of cellulose (3)
Getting back on topic:

Cellulose is a condensation polymer and condensation polymers are formed by the "head-to-tail" joining of two monomers which have functional groups at each end and result in the loss of a molecule, usually water. Cellulose is renewable and a polymer of which the monomer units are B(beta) glucose molecules. 'Insert drawing of cellulose'

What else can you write for 3 marks? I assume they would want to know what polymer it is and how it is formed.
 

Queenroot

I complete the Squar3
Joined
Sep 11, 2011
Messages
7,487
Location
My bathtub
Gender
Female
HSC
N/A
Getting back on topic:

Cellulose is a condensation polymer and condensation polymers are formed by the "head-to-tail" joining of two monomers which have functional groups at each end and result in the loss of a molecule, usually water. Cellulose is renewable and a polymer of which the monomer units are B(beta) glucose molecules. 'Insert drawing of cellulose'

What else can you write for 3 marks? I assume they would want to know what polymer it is and how it is formed.
The 3 carbon and 4 carbon chains
 

enigma_1

~~~~ Miss Cricket ~~~~
Joined
Feb 27, 2013
Messages
4,281
Location
Lords
Gender
Female
HSC
2014
Getting back on topic:

Cellulose is a condensation polymer and condensation polymers are formed by the "head-to-tail" joining of two monomers which have functional groups at each end and result in the loss of a molecule, usually water. Cellulose is renewable and a polymer of which the monomer units are B(beta) glucose molecules. 'Insert drawing of cellulose'

What else can you write for 3 marks? I assume they would want to know what polymer it is and how it is formed.
The loss of n-1 water molecules makes cellulose less polar this reducing it's solubility in water and coz likes dissolve likes. So it exists in plant walls coz it's insoluble in water and it's also strong because of the hydrogen bonding and strong dispersion forces due to the linear structure. It's also used in wool or something. Condensation polymerisation is fast coz it happens at both ends.
 
Last edited:
Joined
Feb 16, 2014
Messages
2,258
Gender
Male
HSC
2014
The 3 carbon and 4 carbon chains
The loss of n-1 water molecules makes cellulose less polar this reducing it's solubility in water and coz likes dissolve likes. So it exists in plant walls coz it's insoluble in water and it's also strong because of the hydrogen bonding and strong dispersion forces due to the linear structure. It's also used in wool or something. Condensation polymerisation is fast coz it happens at both ends.
oh okay fair enough

I doubt they'll ask for three marks. Nonetheless, new question.

Describe the relationship between the acidic and basic nature of oxides of elements as you move across the periodic table. 4 marks.
 

SuchSmallHands

Well-Known Member
Joined
Nov 13, 2012
Messages
1,391
Gender
Female
HSC
2014
oh okay fair enough

I doubt they'll ask for three marks. Nonetheless, new question.

Describe the relationship between the acidic and basic nature of oxides of elements as you move across the periodic table. 4 marks.
pH generally decreases across a period, with metal oxides generally forming basic oxides, semi-metals often forming amphoteric oxides and non-metals forming acidic oxides. However, this trend does not apply to the d-block metals, as the acidity of these metals is directly proportional to oxidation state (eg. CrO (containing Cr2+ ions) is basic, Cr2O3 (Cr3+) is amphoteric and CrO3 (Cr6+) is acidic).

I probably wouldn't include the thing about d block metals if the question was only worth two marks, but I can't think of anything else to add to make this an appropriate response for a four mark question.
 

QZP

Well-Known Member
Joined
Oct 7, 2013
Messages
839
Gender
Undisclosed
HSC
2014
pH generally decreases across a period, with metal oxides generally forming basic oxides, semi-metals often forming amphoteric oxides and non-metals forming acidic oxides. However, this trend does not apply to the d-block metals, as the acidity of these metals is directly proportional to oxidation state (eg. CrO (containing Cr2+ ions) is basic, Cr2O3 (Cr3+) is amphoteric and CrO3 (Cr6+) is acidic).

I probably wouldn't include the thing about d block metals if the question was only worth two marks, but I can't think of anything else to add to make this an appropriate response for a four mark question.
Where do you learn this stuff...
 

SuchSmallHands

Well-Known Member
Joined
Nov 13, 2012
Messages
1,391
Gender
Female
HSC
2014
Where do you learn this stuff...
My option is chem of art haha, I do a lot on the oxidation states of d block metals and I learned this at some point and thought it would fit in here and fill out my answer a little. If it weren't for my option I wouldn't know that, I can assure you.
 

QZP

Well-Known Member
Joined
Oct 7, 2013
Messages
839
Gender
Undisclosed
HSC
2014
Ohh nice! Yeah also I find my option (industrial) relates to back to a lot of things learned in the core. :)
 

Users Who Are Viewing This Thread (Users: 0, Guests: 2)

Top