Last minute chem! (2 Viewers)

[hurikai]

Hey all... after bludging the whole weekend, I've just realised that I'm pretty much clueless about the chem part of science... can anyone just give me a brief overview or list of the topics or concepts I need to know about? Do we have to memorise valencies of transition metals and polyatomic ions and everything? And what reactions do we need to know?

Thanks heaps.

 

[Telekinetik]

Umm. Things like the atomic theory, elements and the periodic table, compounds, chemical formulas, chemical reactions, indicators, energy resources and materials technology.

 

[maiying.n]

i think that u pretty much just need to kno bout the relationships between elements in the periodic table. the bohr/rutherford model, writing word equations, some common chemicals, the reaction types and indicators.
reactions:
combustion
metal + oxygen ---> metal oxide
hydrocarbon + oxygen --> water + carbon dioxide

corrosion (slower form of combustion)
metal + oxygen --> metal oxide

precipitation- soluble reactants react to produce an insoluble product.

acids on metals
acid + metal --> salt +hydrogen

acids on carbonates
acid + carbonate --> salt + water + carbon dioxide

neutralisation
acid + base --> salt + water

decomposition
involve one reactant breaking down into 2 or more simpler substances.

Indicators
Chemicals which change colour in acids and/or bases to show the substance is an acid or base. eg. Phenolpthalein, litmus, universal indicator.

i dont think that u need to kno about valencies and balancing equations coz it only really says stuff bout word equations. good luck

 

[hurikai]

Thanks for that =)

 

[hurikai]

oh god... what's this about indicators? lol I'm clueless...

 

[Neurox]

Know stuff like position of protons, neutrons and electrons in an atom. Transition metals can have a valency of 2 or 3, and polyatomic atoms..im not sure, doubt were gonna get asked about these stuff. Know that if the atom is more positive than negative (ie has more protons than electrons) then the shells will be closer to the nucleus than if it was more negative.

Memorize the easy stuff like acid+metal = hydrogen + salt. Indicators are chemicals that are used to identify the chemical conditions of a substance by changing color. The pH scale matches the color with the pH (acidity or basic) value of the substance.

Distinguish between elements, compounds and mixtures, and distinguish between chemical and physical changes- physical changes are reversible whereas chemical changes are not.Mass no.= no. of protons + neutrons, atomic no.= no. of protons. Relative atomic mass is the average mass number of all the isotopes of an element.

Neutrons are the determining factor of an atom's radioactivity. This is the factor that distinguishes between isotopes of the same element. Note that not all radioisotopes are dangerous. eg. carbon 14 can be used for radioactive dating and iodine 131 for curing cancer.

Know what covelant and ionic bonds are

oh yeh and know some experiments on how to prove if a reaction occurs and a substance is produced, if it really exists.
like for metal+acid= hydrogen +salt, the question might ask, what test do we conduct to know that gas exists. it is the pop test.

 

[Kujah]

oh god... what's this about indicators? lol I'm clueless...

Indicators:
Substances that change colour in the presence of an acid or alkali. It uses the pH scale, ranging from 1 to 14.

1-6= acidic
7= neutral
8-14: basic/alkaline

Examples of indicators: universal indicator, litmus, red cabbage

 

[hurikai]

Cool, all set!

 

[sikhman]

trust me, I did the chem course in about a week and some of that was extension crap. the chem part will be easy, as most of the extended responses aren't on chemistry

 

[simonloo]

LOL Richard! It is me! Your friend Simon! I am writing this after the SC Science. So I guess I can't help you! LOL!

Btw- Burn books tomorow. >.>

 

[hurikai]

You can go back in time and tell me what was in the paper. THAT would help me.

 

[Forum Friend]

You can go back in time and tell me what was in the paper. THAT would help me.

Am I in Yr10? No. Anyhow, you seem familiar; you too, simonloo character.

Well, if I had posted this earlier, I would have wished you luck, and assisted you with utmost effort, but now it's of absolutely no bearing to your performance.

Oh dear God, it appears that your from a pretty dodgy school. (No offence, hurikai.)
Next time, grab the syllabus, hurikai.:mad1:

Wow, that's ambitious - a UAI of 99.5+. You probably are going to do Physics, Chemisty, Accelerated History/Extension 2 Music/Economics/Latin, 4 Unit Math, and 2 U English, right? Wow...you're quite an interesting character.

Anyhow, it appears that these people have helped you.

Apropos after test chem. The answer to the first short answer equipment question is Erlenmeyer flask, a.ka. conical flask. So, it appears that you needed to have paid attention in Yr7. Well, how do I know what was in the test? I don't really, but people here have great memories, and people talk. Oh, yes, there are test papers on the net, right?

I just can't wait to do the SC - sounds fun, and easy, most importantly.

iodine 131 for curing cancer.

Actually, iodine-131 (an radioisotope of iodine, well nuh) is used for treating thyrotoxicosis and thyroid cancer. Also, iodine is used to detect any anomalies with the thyroid gland. Those an advantage of it, but there are disadvantages of iodine-131, such as the radioiodine treatment being harmful, that people who are treated with such a substance are warned to not engage in any carnal knowledge for at least a week; not to go near children; and not to accidentally impregnate someone or something.

 

[simonloo]

You try too hard to sound smart.

 

[sikhman]

and what year would you be in, forum friend?

 

[Forum Friend]

and what year would you be in, forum friend?

Hm? Not yours, sadly enough.
My year [FONT=&quot]*[/FONT] that of yours.

That's a crap guess.

That's what everyone does - well, virtually everyone. It's also likely that this guy/gal is going on to consider Med, LottoX.

You try too hard to sound smart.

Well, if that is to be taken as a compliment, which it isn't meant to be understood as, thank you; however, considering that it sounds like a rebarbative retort, I shall endure that comment.
Ah, I think I know you now - well, no, I don't know you unless you are Lawrie Liu's brother. It says that you school at High. (Ha, High. Don't worry; just forget it.)
Also, that information about iodine-131 is true.

 

[sikhman]

Well i happen to be in Year 9, so I have a feeling you're in my year as well...

 

[simonloo]

Forum Friend- go away. I don't like you.

 

[Kujah]

I just can't wait to do the SC - sounds fun, and easy, most importantly.

I think he/she is either in year 8/9

 

[sikhman]

well, my feeling is year 9, because hsc was n/a, and you can put in 2009, which would be year 9.

or he/she is just being over secretive for no apparent reason and he/she is trying to remain anonymous so as to accentuate our supposed feeling of awe at her/his writing style and knowledge.

Just a theory

 

[Telekinetik]

well, my feeling is year 9, because hsc was n/a, and you can put in 2009, which would be year 9.

or he/she is just being over secretive for no apparent reason and he/she is trying to remain anonymous so as to accentuate our supposed feeling of awe at her/his writing style and knowledge.

Just a theory

I think people who use articulated words to impress their peers are really stupid. I mean, with intelligence comes wisdom, and with wisdom comes the knowledge to use words that are appropriate to their audience.