* Chemistry * Predictions / discussion / aftermath * (1 thread please)

Exothermic

I have a nice four day break 'till Tuesday What does everyone plan on studying and how? Exam papers, book, writing out notes? I'm determined to get my A1!

TheFullDuck

More of an endothermic man myself

Exothermic

Ah sure that's no fun :P Exothermic is where all the fun is! Exothermic woman all the way.

._.

Exothermic wrote: »

I have a nice four day break 'till Tuesday

Same. There's a pizza in the oven and two blurays all with my name on them for today, after that it's 10+ hours of study a day for it until tuesday
I'd really love an A1, but if I maintain my B1 from my last mock i'll be happy enough with it (2% off the A )

macskanadrag

I'll keep on doing previous papers, look up stuff i can never remember like the tests for anions in solution aaaand hope for the best! Hope that it won't be like last year's and hope it won't try to test my overall knowledge like the Biology paper did... :P

Any tips on preparing? Efficiently

nommm

Haven't studied it in the last 3 weeks. Hopefully everything I learnt during the year will come back to me in the next few days!

QueenOfLeon

macskanadrag wrote: »

Any tips on preparing? Efficiently

Past papers, and the types of questions that can be asked for each topic, especially the experiments. Know the titrations inside out, the questions are very predictable. The method of titration is nearly always asked, and very easy to pick up marks on, but if you don't already have a list of steps check the marking scheme for what they were looking for (the rinsing techniques, filling things to the mark, etc).

macskanadrag

QueenOfLeon wrote: »

Past papers, and the types of questions that can be asked for each topic, especially the experiments. Know the titrations inside out, the questions are very predictable. The method of titration is nearly always asked, and very easy to pick up marks on, but if you don't already have a list of steps check the marking scheme for what they were looking for (the rinsing techniques, filling things to the mark, etc).

Aye, cheers for that. I have two or three past papers left that i haven't done yet, so i'll start with those and see what goes worst, study that, revise, do another paper, revise etc etc.

Any *magical* tips? :rolleyes: Like how i will remember the bloody anion tests or i don't know... i don't even know what i don't know... Ugh, time to study:pac:

YodaBoy

Any tips or the questions in section B?. Obviously there's the organic, the thermochemistry, Q4 and the bonding/history ones..but what about Q10/11 and rates or equilibrium or water or what for 7,8,9 ish???

QueenOfLeon

macskanadrag wrote: »

Any *magical* tips? :rolleyes: Like how i will remember the bloody anion tests or i don't know... i don't even know what i don't know... Ugh, time to study:pac:

Erm...NISSAN: Nitrates Iron Sulfate Sulfuric Acid Nitrates

Thats the only one I can remember and I've given all my notes away

Alibear

I have a break until Tuesday too... It'll also be my final exam, yay!

macskanadrag

QueenOfLeon wrote: »

Erm...NISSAN: Nitrates Iron Sulfate Sulfuric Acid Nitrates

Thats the only one I can remember and I've given all my notes away

You're a star! Do mention it if you have more!

Everyone knows OIL RIG, yeah? Oxidation Is Losing (electrons), Reduction Is Gaining.
And the hardness in water - edta titration, indicator: Everyone Robs Bikes: Eriochrome (Black T) Red to Blue. But that came up last year, the bastrd.

Aaaand looking up more now.

TheFullDuck

Viagra is a sex drug - vaporisation, ionisation, acceleration, seperation detection

Red ponies never kick - refinery gas, petrol, naphta, kerosene

Sexy flirty susan finds charlie fascinating - screening flocculation, sedimentation, filtration, chlorination, fluoridation

I transmit sexual diseases - injection, transport of sample, separation in column, detection

Mary eats peanut butter - methane, ethane, propane, butane

QueenOfLeon

macskanadrag wrote: »

You're a star! Do mention it if you have more!

Well I usually used memorising techniques that would probably have been ridiculous to anyone else :P

The one I used for phosphates was PANAMA (if you pretend its spelt wrong >_>)...PAMAMA: Phosphate, Ammonium Molybdate, AMmonium.

macskanadrag

QueenOfLeon wrote: »

Well I usually used memorising techniques that would probably have been ridiculous to anyone else :P

The one I used for phosphates was PANAMA (if you pretend its spelt wrong >_>)...PAMAMA: Phosphate, Ammonium Molybdate, AMmonium.

Oh weird ones are the easiest to remember! I'll have to put in the observation too... Hmmm, PAMOYA, Phosphate, Ammonium MOlybdate, Yellow (ppt) Ammonia (soluble)? But then how do i remember Pamoya? Damn! A bit too weird... At least it's fun

snicket

Anyone got experiment tips? I heard one of the iodine-thiosulphate titrations and the volatile liquid one are possibilities anyway.

I love those memory things Theres that long one on the electrochemical series but are you ever going to need to recite that in the exam?
And flame tests: COB (COpper Blue)
STRED (STrontium RED)
SOY (SOdium Yellow)
PIL (Potassium LIlac)
BAY (BArium Yellow)
...:)

ride-the-spiral

snicket wrote: »

Anyone got experiment tips? I heard one of the iodine-thiosulphate titrations and the volatile liquid one are possibilities anyway.

I love those memory things Theres that long one on the electrochemical series but are you ever going to need to recite that in the exam?
And flame tests: COB (COpper Blue)
STRED (STrontium RED)
SOY (SOdium Yellow)
PIL (Potassium LIlac)
BAY (BArium Yellow)
...:)

Barium, green no?

emma123abc

ride-the-spiral wrote: »

Barium, green no?

It's yellow green in colour according to my book:)

snicket

BAG is just as easy to remember anyway :P

_coley_

shane0312 wrote: »

Just in general, what experiments, likely long questions etc.

We were told sodium hypochlorite in bleach as a redox titration comes up every second year.
Then for the organic ethanal or ethanoic acid.

macskanadrag

The most i have seen being predicted for this year is the volatile liquid one and the hypochlorite in bleach.

Careful with predictions though. I think the SEC science section started to operate on a more "study it all and think" basis than predictable one-liner answers. Last year's chem paper looked like it anyway and then biology yesterday was going against predictions too so i'm wary of the chem paper... It's not necessarily more difficult, but requires a different approach.

Gavarn

With the way the exams have gone this year I just want to clear something up:

Is it definite that they have the experiment questions as:

-Titration Question
-Organic Experiment
-Other experiment (not a titration or organic)

Thanks I'm going to be doing all 3 experiment Q's!

ride-the-spiral

Well question 3 could still be an organic, such as the heat of reaction with HCl and NaOH, but as far as i know it's never been a titration.

And yes the first two are always titration and organic.

Iamcool

Could anyone tell the questions that were asked on the experiments for exam craft for the mock? I really want to know what kind of questions they asked on them like for example in DEBS they asked why you did certain things.

._.

Could somebody help me with this?

My revise-wise book tells me 0.15 : 0.2 is a ratio of 3 : 4.
How do you work out ratios like that?

partyatmygaff

._. wrote: »

Could somebody help me with this?

My revise-wise book tells me 0.15 : 0.2 is a ratio of 3 : 4.
How do you work out ratios like that?

First of all write them out as 0.15 : 0.20

Find the lowest common factor and work it from there.

epicwinning

._. wrote: »

Could somebody help me with this?

My revise-wise book tells me 0.15 : 0.2 is a ratio of 3 : 4.
How do you work out ratios like that?

Multiply by 10:

1.5 : 2

Multiply by 2:

3 : 4

emma123abc

._. wrote: »

Could somebody help me with this?

My revise-wise book tells me 0.15 : 0.2 is a ratio of 3 : 4.
How do you work out ratios like that?

As far as I can tell, it's just to make the ratios easier for you to work with. The smaller ratios were both multiplied by 20, to make them both whole numbers

0.15 X 20 = 3 and 0.2 X 20 = 4, so the ratio 3 : 4 is the same as the 0.15 : 0.2 ratio.

To do it yourself, I can never work it out properly, so I multiply the numbers by 10 or 100 (whichever gets rid of the decimal) and then simplify the ratio... So for this one:
0.15 x 100 = 15 and 0.2 x 100 = 20
The new ratio is 15 : 20, but both can then be divided by 5
So the ratio can be written as 3 : 4, for you convenience when doing the question


[EDIT: Ok so the explanation given above mine is way simpler, don't know where i was going with this!]

._.

Thanks guys, I get that first one now..

This one though.. Even after understanding that first one, I really don't have a clue how they did this next one:

4.545 : 9.09 : 2.27
2:4:1

I also don't see why you never round up that 4.545 at any point

I can kinda see where they're coming from, but I really wish they'd explain things better in the book.. I really shouldn't have to ask people on the effing internet for help to explain what they did

partyatmygaff

._. wrote: »

Thanks guys, I get that first one now..

This one though.. Even after understanding that first one, I really don't have a clue how they did this next one:

4.545 : 9.09 : 2.27
2:4:1

I also don't see why you never round up that 4.545 at any point

I can kinda see where they're coming from, but I really wish they'd explain things better in the book.. I really shouldn't have to ask people on the effing internet for help to explain what they did

Where in the Chemistry course do you need to work with ratios like these?

AFAIK, the only time you ever need to manipulate ratios is in Stoichiometry in the limiting reagent calculations and they're never going to be in ratios that large.

Gavarn

._. wrote: »

Thanks guys, I get that first one now..

This one though.. Even after understanding that first one, I really don't have a clue how they did this next one:

4.545 : 9.09 : 2.27
2:4:1

I also don't see why you never round up that 4.545 at any point

I can kinda see where they're coming from, but I really wish they'd explain things better in the book.. I really shouldn't have to ask people on the effing internet for help to explain what they did

Take the lowest one: 2.27 and use it as 1

So how many times does 2.27 go into the other ones

2.27 goes into 4.545 twice so: ratio is 1:2
2.27 goes into 9:09 four times: ratio is 1:4

therefore:
4.545 : 9.09 : 2.27
2 : 4 : 1

partyatmygaff

I'd say one of the two oxidation of Ethanol experiments will come up this year. The reason behind that is that the Dept. Education have banned the use of hexavalent chromium in secondary schools so we'll be the last year to have actually done those two experiments. That and the equilibrium experiment involving Cobalt Chloride and a Dichromate salt. That experiment contains two banned chemicals.

Joseph...

what experinments do ye think will come up??

ClaireMarie

My teacher has really been predicting bleach and ethanal for the first too!
Bleach especially - as it has never been up.
If winkler and benzoic acid come up for Q 1 and 2 - SOMEONE. WILL. PAY.
Lol, I had a good teacher - but for some reason I just hate those 2!

Phareon

Joseph... wrote: »

what experinments do ye think will come up??

Our teacher's tipping Bleach titration and Rates of Reaction, i.e NaOH and HCl !!
All of the Organic experiments have come up before, so just go over Exam Papers!!!
And like the previous poster said, the ones with banned chemicals are likely!!

._.

I'll cry if ethanal comes up, I really can't do that calculation.

DM360

partyatmygaff wrote: »

Where in the Chemistry course do you need to work with ratios like these?

Empirical formula questions have numbers and ratios like that.

Preparation for ethanal or ethanoic acid or possibly a question with both for the Organic Chemistry Exp.

Volatile liquid or heat of neutralisation for the other I've been told.

And another acronym: OPRN (remember that how you will ) for electrochemistry. Oxidation is at Positive Electrode, Reduction at Negative

._.

ok, does anybody else actually have this godforsaken Chemistry Revise Wise book?
Page 99/100, does how they got to 1 mole of MgO = 40g make sense to anybody? They literally just wrote it down and gave absolutely no explanation as to how they got there..

epicwinning

._. wrote: »

ok, does anybody else actually have this godforsaken Chemistry Revise Wise book?
Page 99/100, does how they got to 1 mole of MgO = 40g make sense to anybody? They literally just wrote it down and gave absolutely no explanation as to how they got there..

mass (in grams) = MR(n)

n = 1 , MR = 16+24 = 40

m = 40*1
m = 40g

Phareon

._. wrote: »

ok, does anybody else actually have this godforsaken Chemistry Revise Wise book?
Page 99/100, does how they got to 1 mole of MgO = 40g make sense to anybody? They literally just wrote it down and gave absolutely no explanation as to how they got there..

Mr of Oxygen is 16, so 1 mole O = 16g,
Mr of Magnesium is 24, so 1 mole Mg = 24g
24g + 16g = 40g

^^ Ninja'd

Exothermic

._. wrote: »

ok, does anybody else actually have this godforsaken Chemistry Revise Wise book?
Page 99/100, does how they got to 1 mole of MgO = 40g make sense to anybody? They literally just wrote it down and gave absolutely no explanation as to how they got there..

Go to your periodic table Mg = 24 O = 16. Add 'em up, you get 40. Hence, MgO = 40g.

Exothermic

Whoops. :P Well, that question certainly got answered.

._.

grrrrr, is it too much to ask for them to actually tell you where they're pulling these numbers from?

Thanks guys, chemistry calculations are really not my thing.

epicwinning

:P

And yeah, I have the Revise-Wise Chemistry. It's just a smaller version of the Chemistry book we used (Understanding Chemistry, I think it was called...) for the last couple of years.

ride-the-spiral

partyatmygaff wrote: »

Where in the Chemistry course do you need to work with ratios like these?

AFAIK, the only time you ever need to manipulate ratios is in Stoichiometry in the limiting reagent calculations and they're never going to be in ratios that large.

Empirical formula most likely

_coley_

Could anyone explain to me in simple terms how to balance a redox equation thing with the oxidation numbers?
Teachers a dud

River Song

_coley_ wrote: »

Could anyone explain to me in simple terms how to balance a redox equation thing with the oxidation numbers?
Teachers a dud

I'll do out one very quickly if you want?

YodaBoy

Anyone have tips for the experiments they could throw into section 2?? Maybe equilibrium ones??? Dont know those ones at all

River Song

Okay, did 2002 balencing REDOX equations Question:

stealinhorses

Awesome whiteboard.

River Song

stealinhorses wrote: »

Awesome whiteboard.

Reads, of Nassau St., like 15 Euro.