equink:

Can you please help me to solve this question?


10cm^3 of a hydrocarbon C4Hy was allowed to react with an excess of oxygen at 150°c and 1atm. There was an expansion of 10cm^3 in volume. Deduce the value of y.

Is the \"expansion\" stated in comparison to the volume of the hydrocarbon AND excess oxygen or to the volume of hydrocarbon AND reacted oxygen?

hahaha I think we might be in the same school... Q10?

Anyway, I think the expansion of 10cm^3 refers to the total volume of gaseous products after complete combustion. (Ie, Vol of CO2 & H2O (g) + vol of excess unreacted O2 = 20 cm^3)

To solve,
vol of CO2 + vol of H2O (g) + vol of unreacted O2 - (10 cm^3 of C4Hy + vol of reacted & unreacted O2) = 10 cm^3

10 cm^3 = vol of CO2 + vol of H2O - 10 cm^3 - vol of reacted O2
= 40 + 10 (y/2) - 10 - 10 (4+y/4) [based on chemical equation, multiply by 10 cm^3 since 1 'mol of C4Hy gives 10 cm^3 -- since it's gas, volume can multiply throughout].

y = 8

Took me quite some time to get it too, hope this helps!

Jonathan Lim:

Since my son is in ACSI , he has 2 bonus points to ACJC . However , he wants to go NJC but did not meet the cut off point . Should he put NJC first ? But he would lose the 2 bonus points to ACJC by not putting ACJC as the first choice . Would NJC accept his appeal if it isn't his first choice ?

Depends on the school (NJC) - anyway, isn't JAE over? o__O. I think your son should put ACJC as first choice to secure the 2 bonus points and NJC second. Although, this depends on his score itself: If he can qualify for ACJC without the 2 bonus points, then by all means put NJC first and ACJC second. If not, might want to reconsider and place ACJC as first choice in order to ensure 2 bonus points and admission to a school. A rather good one may I add :). I'm sure if you have good enough achievements, NJC might consider your appeal even if it's 2nd choice, if there are sufficient vacancies. Not confirmed though!! Good luck :).

Hi, that's quite far :roll: . Anyway, check out this website, http://gothere.sg

Aww.... must it be school uniform or is PE acceptable?


Haha going2school, yep! Yay future fellow school mate:). Are you a girl or guy...? I'm a girl . IB sounds interesting, but heard there's a lot of coursework & PW involved.

Haha yay if you're going to NJC we might end up school mates! I sure hope it's going to be a pleasant 2 years. :roll:


hey Skyed, good luck for your school choices! TJC seems ideal since it's only 5 mins from your house, green uniform! Where else are you planning to go?

Hi I'm in a similar dilemma! I live around Serangoon too. I'm quite introverted as well and because of that I've decided to choose NJC, I think there will be more opportunities open as opposed to VJC where people are more outspoken. Also, I have friends who will be there too so that helps! And NJC's building is nicer over VJC's haha no offense, and that shouldn't be a deciding factor actually but I quite like NJC. About the stereotypes, there are generally two responses: Majority claim that it is a mugger school; fewer claim it is not. I guess ultimately it depends on the type of people you mix with and I'm sure in NJC we'll be able to find our own groups of people? A senior of mine says that in NJC, there are students coming from all types of schools so there's diversity. Oh apparently the IP stream doesn't mix with the O levels at all, they are in the same class for 6 years :(. So at most we'll only meet them around in CCA? Hope this helps :D. Again, not an expert on any school but I hope I won't regret my choice and neither will you! All the best :D!

isadoralizzy:

btw, where do you live?

Hi, thanks for sharing :). I'll probably be entering NJC! I live in Serangoon area, it's not very near njc but neither is it near VJC (which was my other consideration). Look forward to starting school there

jessting, I think you should just place RJC as first choice & hope for the best when you appeal, over HC based on distance alone - I think both schools are more or less equally matched academic wise. As for your other choices/ safety net, I think you could consider VJC, TJC, NJC, ACJC, etc etc, or ACSIB. Should be able to get into most without any problems. All the best!

lebookworm:

Hello! I live in the Serangoon area too!

Contrary to popular belief, NJ is not a boring school. I love NJ, just like one loves his family. NJ IS family, as a matter of fact. However, we do not have elitism. We love anyone and everyone. In NJ, there will be a lot of interaction opportunities across the levels as well and both the juniors and seniors are really close! (We juniors are always sad to see the seniors go after their A levels) School life is really vibrant to me as there are lots of activities going on and lots of things to discover! Trust me, you'll be outgoing when you come to NJ! Our Orientation will open you up and soon you will be chatting away like there's no tomorrow.

As for the academics side, I'm not too sure about the JC curriculum, but the tutorial notes are a lot less thicker than in HCI or RI(JC). As for the teachers, it really depends as we both have very strict teachers as well as very kind and encouraging teachers, but both kinds want you to do well.

For the CCA side, NJC is legendary for its strong canoeing team. However, I'm not too sure for the rest.

I hope you find this useful and that you will come to NJ! We welcome you with open arms!

Hello! Thank you very much for your sharing haha, I'm definitely considering nj haha. I heard your principal can be quite fierce! :P. Are you from junior high/ secondary, or which year? :). Anyway it's always nice to see people liking their school, and hopefully I'll join you & everyone else soon!

isadoralizzy:

Actually the people in NJ depends on who you mix with. After all, there are some super quiet ones who never say anything to others except to those in their clique. Then there are also those who are super hyper and crazy - those people are really outspoken and they can just socialise with everyone. Maybe, it is changing, I have no idea, but being in the IP requires the students to be more interactive and outspoken, because, these students with better academic achievements and sociable attitude tend to be given much more opportunities on the local as well and in the international field.

Did you go for NJ's open house?

Hi, yeah I went for NJ's open house. I quite like the school compound, looks very nice and the Oasis is a nice place :). The students are generally quieter than vj's but yeah, probably different groups? Anyway thank you very much for your input, I'll definitely consider NJ!

Hey isadoralizzy! are you from nj? I'm considering it as one of my choices & if possible could you share how it is like there, thank you!


jesstingwugui, I think you should try for rj or hc, I'm sure you'll be able to get in through appeals, you did score quite well :D. As for rj/ hc, might want to choose based on distance & convenience. If you're planning on appealing, you should put the one you'd like to get in most as first choice for sure. Good luck!!