HL Chemistry paper 1 and 2

[Sofia.]

 

 

 

 

(TZ2) I'm super frustrated with the amount of silly errors I made in paper 2 (not reading the question properly, unit conversions etc.) I hope it won't have cost me a 7. I cannot remember which question this was, probably 9, but we had to work out the bond angle of SF4. I got the shape right but I never learnt or came across bond angles for see saw shapes so I guessed 107. What did you guys get for that?

I said the same thing. 107 for one and <120 and<180 for the other one.both had a lone pair. What did you writr for the question were they asked about the covalent bond between hydrogen and carbon?

Shared pair of electrons closer attracted to carbon due to its higher electro negativity though I squeezed that last bit in right at the end, may not get the mark. Regarding the percentage error, I got 60 but I used 0.05 not 0.025 mol to work out delta H (the first of my silly mistakes!!) I believe the correct answer is around 20%.

 

For the delta T I wrote 6 degrees, which I only noticed the last 5 min. But with that I got 22%, so 20% sounds about right... Hopefully I only lose the one point on the delta T but get the points with ECF

 

 

 

I got Del T = 5.2 C? Did you extrapolate the line of best fit from the max temperature on to the y axis and use that temperature reading or directly use the highest reading on the graph (and then subtracting from the same initial reading)? 

 

Also what were your major sources of error? I wrote heat loss to the environment, and use of a styrofoam cup to minimize heat loss. 

 

 

I got Delta T 5.6 from extrapolating, but I wasn't sure if that was correct or not - finally decided to extrapolate to compensate for loss of heat to surrounding, cause that is what we did in our IAs. 

[Runner22909]

Extrapolating would make sense too, so idk.

[Sofia.]

Extrapolating would make sense too, so idk.

 

I even wrote that it was an unclear question haha! Well, hopefully there will be a large interval that is correct. 

[anotheribkid]

 

 

 

 

(TZ1) For paper 1, what was the answer to what would change the Kc value. I put C (increase in concentration) but I'm not sure.

There was another question where there was two arrows. It went something like hydrocarbon -- X -- CH3CH2NH2 and said find x? Does anyone remember it.

 

For paper 2, I remember doing 6 and 8 for section B.

 

I wasn't sure about the economic need for catalyst in the contact process on question 6? 

Left a whole pH question blank even though I knew the ph = pKa - [weak acid]/[base]

uh I put no change for that one. I thought Kc is only depended upon temperature. Since it was constant temp i think Kc remains the same. 

 

My bad. The question I was referring to was what affects k, the rate, not Kc. But I put no change for the Kc one as well!!

 

I thought that question was actually about Kc and how it would decrease, where one answer was a decrease in temperature - which would be correct. 

And the question with two arrows, I thought the answer was an alcohol - I don't remember what A was for the answer, B had added a Cl and an H which wouldn't have been possible with the bonding structure (there would be one extra H as the hydrocarbon was already saturated), C was the alcohol, and D was a halogenoalkane that ended with Cl2 which I don't think is possible (but it may be, I didn't study for organic at all before the test)

 

For paper 2, I also ended up doing questions 6 and 8! For the economic need, I said that it increases the rate of reaction - does not affect the yield but producing production speeds up

 

Yeah, but there was also a question that said rate = k [c]  and then it asked what would affect the value of k. That's the question I'm referring too. I guess I got "X" question wrong because i put B, with the one Cl.

Yeah, I said the catalyst increases the rate of reaction as well, but I wasn't sure if that completely answered the question, so I said the increased rate of reaction allows for the preservation of time and resources.

Since you did eight, do you remember what you got for the first pH question. I think it said find the pH of CH3COOH?

 

Oh, I don't even remember that question  

I think you'll get the points for the catalyst question, it was only worth two marks so you should be fine!

For question 8, I got around 3 for both of the pH questions

[mhelof]

 

 

 

I did option B and E... they were alright I think. Better than other papers : )

 what did you get for question of the comparing structures of ketone and aldosterone? 

 

Ketone and aldosterone? Did you mean cholesterol and aldosterone? 

 

sorry...yes it should be cholesterol and aldosterone..i mess up with my name

 

Well tbh we didn't even do the organic chemistry in class (how nice) and I had to do it on my own so I'm not good at this... but I believe that

my similarities were: alcohol and methyl

my differences were: ketone and aldehyde

Although I'm super bad at this so it's most probably very very wrong.

[dani_alencar24]

 

 

Hey guys, what did you get for the 3rd question in P1? it was the PV=nRT thing 

and another question towards the end: the pH change when NaOH is added to water.. was the pH 10 or 12 at the end??

I wrote ph 10 but pure guessing. NaOH should be at ph 14, and after adding 1dm3 of water, I expect it to fall about 4 pH. 

 

Btw for question 3, I wrote the one with 10^3 but it now regret caz i know the ans shud be the one with 10^-3 because of conversion of units.

 

What did you for question 2?

 

I was hesitating and wrote pH 12 it's wrong i know...

 

uhmm.. i don't remember really, but i narrowed it down to the Mr at the top (44) which was answer B or Mr at the bottom which was answer C I think? and I chose the latter option.. i'm still baffled by this question.. 

 

 

I actually took the time to calculate everything and the answer was 10 at then so yea B

[Hassan76]

The answer asking for the mass in grams I think it was a, as I do not remember the choices

But I know how to do it.

Edited May 17, 2015 by Hassan76

[sam1996]

The answer asking for the mass in grams I think it was a, as I do not remember the choices

But I know how to do it.

Which question was this?

[Hassan76]

The answer asking for the mass in grams I think it was a, as I do not remember the choices

But I know how to do it.

Which question was this?

The one that had Mr = 44

[sam1996]

The answer asking for the mass in grams I think it was a, as I do not remember the choices

But I know how to do it.

Which question was this?

The one that had Mr = 44

Cool, I seem to remember getting A too.

[Klauu]

The answer asking for the mass in grams I think it was a, as I do not remember the choices

But I know how to do it.

Which question was this?

The one that had Mr = 44

Cool, I seem to remember getting A too.

Same here, A!!

[Master_Domain560]

Did anyone do question 7 on section B  Chem HL ? Seems as If no one did.  (TZ2)

Edited May 19, 2015 by imperative560

[dhruval.shah]

How does everyone feel about the Chem HL P1 and P2 TZ1 ? 

[dhruval.shah]

How does everyone feel about the Chem HL P1 and P2 TZ1 ? 

Anyone?

[graceundertones]

I found paper 1 really hard I think I literally got 8/40, and paper 2 I freaked out and I forgot how to do every calculation except q=mcAt I did q 7 and 8. I honestly think I failed.

[SailinWind]

 I did the TZ1 exam and I don't think I did well in Paper 2 especially since I am not good with calculations. How did other people in TZ1 feel about the chem exam?

[Daksh Saksena]

Im doing some mole concept questions and I’m getting equations wherein we have to divide 7.75 by 6.022 and .452(181.19 g)

So I’m just wondering whether these hard questions would come in Paper I, does IB expect us to do this without a GDC??