FSN Chemistry Unit 4 Exam - Answers (By Collin)

[nak]

for short answers question 1 ii.

according to the "internet" the answer is actually Pa (Protactinium)
the first member in the group is Actinium itself. so that leaves U as the 4th member of the actinides

but in the heinemann text book in the glossary it says acitnides are elements betwwen 90-103 which would make U the 3rd.. lets just hope VCAA accepts U cos thats what i put

[Collin Li]

for short answers question 1 ii.

according to the "internet" the answer is actually Pa (Protactinium)
the first member in the group is Actinium itself. so that leaves U as the 4th member of the actinides

but in the heinemann text book in the glossary it says acitnides are elements betwwen 90-103 which would make U the 3rd.. lets just hope VCAA accepts U cos thats what i put

There actually happens to be no consensus on whether Actinium should be included in the actinides series or not. The VCAA periodic table does not include Ac in it's periodic table, therefore the right answer to them should be U. I think VCAA will also accept Pa, if enough examiners are noting this as an answer (although I highly doubt anyone would have put Pa, unless they are very well read in chemistry).

[kingmar]

Logically, the answer is U.

The actinide series is not listed in the study design.

Only Uranium is of importance from the Actinide series as far as VCAA are concerned due to fission. You're not expected to learn Actinium, Polonium etc etc. because for VCE purposes they're not important.

Protactinium shouldn't be accepted as an answer based on textbooks and this theory. I assume the majority of students just see Uranium and put the answer as U.

But knowing VCAA, they probably will accept it because of what coblin said. Next time though, it might be best to pick the obvious one.

[AkirA]

Question 20 is wrong - it's C, not D. I interpreted it a different way.

I have maintained it was C from the beginning. Did you choose D?

I chose C. I was reading the posts and some people were saying it was D with totally flawed logic.

[salt'n'sugar]

hello guys,

seems like i lost 3 marks max i was stupid enough to screw up the ratio for the aluminum pot and related question. ill get consequential marks full for the rest i asked my teacher on that one . BTW the structures needed to show the full bonds so did you just shorten them in your answers?

Coblin what enter did you get in VCE?

Q20. i think i put D because i was thinking the amount of energy from each of the three different sources and how much they contribute to the electricity generation. All sources use their total amount of energy but it is the turbine that converts most (98%) of its energy into electricity, compared to about 30 % of the coal going to steam, rest lost as heat. as for the steam heat losses occur but some percentage of steam's energy passes through to the turbine. that was my thinking I'll write it out better if you do not understand . i understand your answer though

Salt'n'Sugar

EDIT:: what does one have to do to become like a maths/chemistry/physics mod here or one of them? i would really be willing to help out.

[Collin Li]

hello guys,

seems like i lost 3 marks max i was stupid enough to screw up the ratio for the aluminum pot and related question. ill get consequential marks full for the rest i asked my teacher on that one . BTW the structures needed to show the full bonds so did you just shorten them in your answers?

Coblin what enter did you get in VCE? and can you really explain in simple terms Q20. i think i put D because i was thinking the amount of energy from each of the three different sources and how much they contribute to the electricity generation. All sources use their total amount of energy but it is the turbine that converts most (98%) of its energy into electricity, compared to about 30 % of the coal going to steam, rest lost as heat. as for the steam heat losses occur but some percentage of steam's energy passes through to the turbine. that was my thinking I'll write it out better if you do not understand .

Salt'n'Sugar

EDIT:: what does one have to do to become like a maths/chemistry/physics mod here or one of them? i would really be willing to help out.

I didn't pay full attention to the questions, especially since I had to draw out the structures in ASCII art form.

I got 45 in Chemistry and got 99 for my ENTER.

I know what you mean for Q20, but I strongly believe the question did not ask for what you thought it meant.

It asks for how much of each form of energy do we need to produce a "fixed output of electrical energy"? So lets just make that "fixed output" equal to a 100 units of electricity: so it's saying tell me how much chemical energy I need to give me 100 units of electricity. Tell me how much steam energy I need to give me 100 units of electricity, and how much mechanical energy I need to give me 100 units of electricity.

Making up numbers here, lets say we'd need 300 units of chemical energy in coal to make 100 units of electricity. Lets say that 300 units of chemical energy becomes 200 units of steam energy, and 100 units of heat. Those 200 units of steam energy would create 100 units of electricity as well (because 300 units of chemical energy produces 200 units of steam, and consequentially, 100 units of electricity).

Now, these 200 units of steam would split up into 150 units of mechanical energy, and 50 units of heat, so that the 150 units of mechanical energy would then give 100 units of electricity, and 50 units of heat. So we have chemical > steam > mechanical.

It's basically just testing your knowledge of the cumulative efficiency of the steps. The steps that occur earlier are going to require more input than the later steps, because there are more energy transformations, and hence more energy losses involved.

[salt'n'sugar]

But you got 45 plus in the four best subjects who which scale heaps but 99 enter thats puts things into perspective!

EDIT:: what does one have to do to become like a maths/chemistry/physics mod here or one of them? i would really be willing to help out.

[Ahmad]

Maybe you can express your interest to Enwiabe. There is a thread on it in the announcements section. There are already 2 sciences/math moderators, I'm not sure if anymore are necessary until we get more members.

And uh, coblins performance is upper 99, except for english, which lowered his mark significantly.

[salt'n'sugar]

you mean not actually 99.00.. like 99.5 ish

thanks, ill talk to enwiabe well ill just help out in the maths alone or science alone or if you add french or music or anything else since i did like 6+ VCE 3/4 subjects ill help out.

anyways i always wanted 45 + in my subjects like cob's main 4 but i just make stupid mistakes though i no the whole content it really annoys me!

[kingmar]

Ain't that the truth. Stupid mistakes > me

Methods, Chem... Now December 17th will be VERY interesting... English is so killing me chances of a 98.

[Collin Li]

you mean not actually 99.00.. like 99.5 ish

thanks, ill talk to enwiabe well ill just help out in the maths alone or science alone or if you add french or music or anything else since i did like 6+ VCE 3/4 subjects ill help out.

anyways i always wanted 45 + in my subjects like cob's main 4 but i just make stupid mistakes though i no the whole content it really annoys me!

I got 99.00 with 45+, but that's because I got 36 in English. It's much easier to get a 99 if you have a decent VCE English score.

[Ahmad]

Mid 30s for English (which gets scaled down too) make it rather hard to get a 99+!  :wink:

[Pencil]

thanks, ill talk to enwiabe well ill just help out in the maths alone or science alone or if you add french or music or anything else since i did like 6+ VCE 3/4 subjects ill help out.

we have a french forum. Feel free to join it  
That might bring our numbers up to like... 6 haha