Random Questions

[lanvins]

1. In gravimetric analysis why would the calculated result be to low; if the mass of the fertiliser was recorded
incorrectly. The recorded mass was 0.2 g higher than the actual mass?

2. Is there an easy way to remember the solubility table for the exam?

3. What common acids and base formulas do we need to know?

4. How would you identify which chemicals undergo odixation in the following, also which is the reductant and oxidant?2AgBr(s) -----> 2Ag(s) + Br2(g) ? (is there a way of doing it without using oxidation numbers)

Thankz

[Mao]

1. recorded too high, but still the same final weight => lower calculater percentage composition

4. oxidation number is easiest =]

[Collin Li]

Solubility table:

You have a data book - it's not on it. Do you really expect VCAA to expect you to rote-learn it?

I think this aspect of the course has been removed (it was very unpopular to begin with anyway - I can't think of a VCAA example which tested your knowledge of solubilities.)

Common acids and bases:

Acids: HNO3, HCl, H2SO4, organic bases with -COOH
Bases: NH3, NaOH (any metal hydroxide), metal carbonates ( anions)

You probably don't need to know any more than that. Just remember the fundamental definition of an acid and a base (a proton donator and acceptor, respectively)

[lanvins]

Solubility table:

You have a data book - it's not on it. Do you really expect VCAA to expect you to rote-learn it?

I think this aspect of the course has been removed (it was very unpopular to begin with anyway - I can't think of a VCAA example which tested your knowledge of solubilities.)

But don't you need the solubility table for the states? I heard people lost marks for not including the states

[doboman]

I heard that aswell. 1 mark per paper i think, as in they dont take it off everytime. Whats the Chem exam marked out of?

[Mao]

I heard that aswell. 1 mark per paper i think, as in they dont take it off everytime. Whats the Chem exam marked out of?

~90 marks

you dont necessarily need the solubility for states, these should have become pretty automatic. just know that

Ag+ is a precipitating agent [will precipitate most things],
group I ions and nitrates are all soluble [always],
Barium Sulphate and Lead Sulphate are insoluble,

and your common solutions [sodium carbonate, ammonia/ammonium, etc] are all soluble [obviously xD]

[bucket]

This whole thing about including states is ridiculous! I've seen chemical reactions where products which are normally aqueous come out as gases!