Higher Chemistry 2019/2020

gustapo

for higher chemistry

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Reply 1

username4250206

How is everyone finding the course so far? We have just about finished the first unit, nice and short :smile:

. Honestly I can't wait for unit 2 since that was the most enjoyable at N5

Reply 2

x.nat.5.x

We are starting off with unit 3 and it is very difficult, considering I found chemistry very easy at nat 5 this is quite a contrast. We are doing unit 3 to get the hardest unit out of the way first, is anyone else doing this?

Reply 3

username4250206

Original post by x.nat.5.x

No, we have been doing unit 1, what is unit 3?

Reply 4

x.nat.5.x

Original post by Valeriex

No, we have been doing unit 1, what is unit 3?

Chemistry in society: so far we gave done, percentage yield, atom economy and molar volume calculations which are straight forward but the equilibrium is pretty tough to get your head around

Reply 5

Catriona23

Original post by x.nat.5.x

Chemistry in society: so far we gave done, percentage yield, atom economy and molar volume calculations which are straight forward but the equilibrium is pretty tough to get your head around

Yeah we’re doing that too, finishing the unit on the 24th with a delightful test :/

Reply 6

x.nat.5.x

Original post by Catriona23

Yeah we’re doing that too, finishing the unit on the 24th with a delightful test :/

I have already had a test on it, pretty sure it went terribly

Reply 7

username4250206

Original post by Catriona23

Yeah we’re doing that too, finishing the unit on the 24th with a delightful test :/

Original post by x.nat.5.x

I have already had a test on it, pretty sure it went terribly

Oof I'm not looking forward to that. Sounds like that unit is quite small then, since we've now finished unit 1. Unit 2 must be huge

Reply 8

Catriona23

Original post by Valeriex

Oof I'm not looking forward to that. Sounds like that unit is quite small then, since we've now finished unit 1. Unit 2 must be huge

My teacher said there are loads of little sub units to Unit 2 but they’re only like 3-4 lessons long each

Reply 9

username4623278

so I have a question, like many others we have finished the first unit 1 and we have a test. so I've been looking at past papers and I found the following question:
An element contains covalent bonding and London dispersion forces.
The element could be
A boron
B neon
C sodium
D sulfur

I get why It isn't B or C but what about A or D? I was taught that every type of bonding had LDF so how can I tell between A or D? I've even asked my teacher but even she couldn't get an answer which I find bizarre.

Reply 10

username4250206

Original post by The_RobDob

It is D. Born exists as a covalent network (along with Silicon, Diamond- graphite/diamond not fullerenes) The only elements/bonding that doesn't have LDFs are:

- Covalent Networks structure
- Metallic structure/ lattice
- Ionic Bonding ( I think- not 100% sure about this one)

You should know that Boron is a covalent network- it is in the course specification. Take a look at it here , it is really useful with the mandatory knowledge, this is really the only thing they can put problem solving with. Hope this helps and is correct, I am doing higher this year as well so please correct me if this is wrong

Reply 11

username4623278

Original post by Valeriex

thanks for the reply!

I did know that boron was a network, but I was taught that LDF were present in everything, (even in networks) in the spec it says "London dispersion forces are forces of attraction that can operate between all atoms and molecules" if they can operate between all atoms and molecules what stops it from acting between networks?
I apologise If I've misunderstood something really obvious...

Reply 12

Catriona23

Hey guys, wondering if someone could help out with this question please?

Reply 13

JoS000

Hello! I am resitting my higher chemistry and I know the course like the back of my hand, if your needing any help with questions then I’ll be happy to help!

Reply 14

N3W

Hey could someone explain the highlighted question, the answer is A but I am not sure why. Unable to ask my teacher as I am unable to go into school at the moment. Thanks

Reply 15

username4250206

Original post by N3W

Hey could someone explain the highlighted question, the answer is A but I am not sure why. Unable to ask my teacher as I am unable to go into school at the moment. Thanks

1. So you need to remember from nat 5 OIL RIG (Oxidation is loss of electrons, reduction is gain)

2. Then you split up the formula for SnCl2. Remember making forumulas from Nat 5 (We used SVSDF -symbol, valency, swap,divide, formula- you might have used something different.) So that means that the 2 at the end of the Cl comes from the Sn ion and it would be a 2+ ion since it is a metal (and metals tend to lose electrons so they become positive)

3.Again because of SVSDF on the products side of the reaction the Sn becomes a 4+ ion. It has lost a further 2 electrons from 2+ to 4+. Which means it has been oxidised.

To be honest, this question was a lot easier to with the answer highlighted. But the main thing to do is to know how to split up formulas into their ions. I really hope this made sense.

Reply 16

N3W

Hey would someone be able to explain question 3 to me

Reply 17

4TheBrighterSide

Original post by N3W

Hey would someone be able to explain question 3 to me

Hi, sorry for the late reply, I don’t know if you’re still in need of help with this question but nonetheless I’ll explain it.

So, for these types of questions there is always a technique to follow and that is to use molar proportions in order to find the final volume. You always use the the reactant that the equation is for so in this case propane and you evaluate the volume of all the other compounds in the equation based on its volume, eg 5O2 will be 150cm^3, however the question tells you that 200cm^3 is reacting with the propane so you do a simple subtraction and get 50cm^3. From here, you just use molar proportion to calculate the volume of only the gas formed and add that to the remaining reactant volume give you a calculation of 50+90 giving you the final answer of 140cm^3 which is C.

I hope this helps, I’m not the best explainer :/

Reply 18

daymeetsnight

Anyone have some advice on how to do open ended questions. They’re always my worst suit.

Reply 19

4TheBrighterSide

Original post by daymeetsnight

Anyone have some advice on how to do open ended questions. They’re always my worst suit.

I would recommend firstly analysing the question and breaking up the words. Find out which topic(s) the questions is mainly referring to and after that you should have a rough idea of what they want you to say linking to that topic. If you can’t think of anything specific, as long as you identify the correct topic you will gain marks, just make sure to stay writing factual information. It can help to attempt the open ended questions right at the end after you finish the rest of the paper as you will have gained more knowledge throughout, but that’s just preference. You should practice and have your teacher mark them with you to build your confidence with them. Have you had your prelim yet?