• Congratulations to the Class of 2024 on your results!
    Let us know how you went here
    Got a question about your uni preferences? Ask us here

Need Help on these questions! (1 Viewer)

cook E

New Member
Joined
Jan 17, 2011
Messages
28
Gender
Male
HSC
2011
Q1. Have no clue
Q2. Have no clue
Q3a. I know the by product is water, but I don't get how the polymer is an ester.
b. Do we just divide 60000 by the polymers molar mass? Or do we have to subtract
water aswell. I'm confused.

Btw I don't have the answers for these questions.
 

Attachments

MNsz

New Member
Joined
Jul 3, 2011
Messages
5
Gender
Male
HSC
2011
I think you divide it by the polymers molar mass.
 

muzeikchun852

Active Member
Joined
Mar 29, 2009
Messages
1,590
Gender
Undisclosed
HSC
2011
1) (i) you are right.
- (ii) Mg > Zr > Zn > Ni
- (iii) should be (-)

2 (a) it's right.
(b) check you note. it should be something - radiation going in the tube. ionise the argon ion in the air, etc.

3 (a) it is an ester because it has the COOC group, but glycolic acid doesnt, so it's not an ester.
however, the question only requires you to answer why it is classed as polyester - just say it undergoes a condensation reaction.

(b) find the molar mass of PGA - then 60,000 divide by that number.
 
Last edited:

cook E

New Member
Joined
Jan 17, 2011
Messages
28
Gender
Male
HSC
2011
1) (i) you are right.
- (ii) Mg > Zr > Zn > Ni
- (iii) should be (-)

2 (a) it's right.
(b) check you note. it should be something - radiation going in the tube. ionise the argon ion in the air, etc.

3 (a) it is an ester because it has the COOC group, but glycolic acid doesnt, so it's not an ester.
however, the question only requires you to answer why it is classed as polyester - just say it undergoes a condensation reaction.

(b) find the molar mass of PGA - then 60,000 divide by that number.
Hey man, can you elaborate on 1ii?
I get the others thank you very much.
 

muzeikchun852

Active Member
Joined
Mar 29, 2009
Messages
1,590
Gender
Undisclosed
HSC
2011
Hey man, can you elaborate on 1ii?
I get the others thank you very much.
galvanic cell flows from anion to cation (negative to positive) right? and more reactive metal displace the less reactive metal right?
so firstly, the polarity of Zr with Mg is (-), hence Mg > Zr
secondly, the polarity of Zr in the next two is (+), hence Zr > Ni, Zr > Zn
but to see whether Zn is more reactive than Ni, or the other way around, you have to use the potential differences.
the greater the voltage, the higher the reactivity between metal, hence Mg > Zr > Zn > Ni.
 

cook E

New Member
Joined
Jan 17, 2011
Messages
28
Gender
Male
HSC
2011
galvanic cell flows from anion to cation (negative to positive) right? and more reactive metal displace the less reactive metal right?
so firstly, the polarity of Zr with Mg is (-), hence Mg > Zr
secondly, the polarity of Zr in the next two is (+), hence Zr > Ni, Zr > Zn
but to see whether Zn is more reactive than Ni, or the other way around, you have to use the potential differences.
the greater the voltage, the higher the reactivity between metal, hence Mg > Zr > Zn > Ni.
Oh ok I get it thank you man.
You're repped =D
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top