I know this may be a bit early but a lot of people I know are already starting to struggle and some revise for this test .I could't find a thread for CHEM1 on student room so thought I should create one and get things under way.Feel free to discuss anything relating to Chemistry Unit 1 here. We are currently doing sub shells so ye.
1. a) i) 1.6734*10^-24 ii) B b) i) 20% ii) Same arrangement of electrons in shells c) between 3000-10,000 they will probs allow ( i got this wrong stupidly put like 17,000) d) B+(g) --> B2+ (g) + e- e) Removing it from a positive charged ion which is attracting it
2. a) i) something like 0.00879 ii) 0.75*a)i) iii) 0.00126 cubic metres b) thermal decomposition c) only solid product, others are gases and will disperse
3. a) i) d block ii) strong metallic bonding between ions because theres lots of valence electrons and also size of ions is small due to large amount of protons causing strong attraction between positive ions and negative delocalised electrons iii) OOO OOO labelled with + inside ions iv) layers of atoms which can slide over each other. b) i) 1s2 2s2 2p6 3s2 3p6 4s2 3d6 ii) 1,6,1,6,12 & Calcium Carbonate/ Calcium Oxide
4. a) i) Hydrogen bonds ii) basically include all delta partial charges, the lone pair on each nitrogen and a dotted line going from lone pair to hydrogen with NHN in a straight line b) Lone pair of electrons on nitrogen forms co-ordinate bond with boron atom. both electrons in bond come from nitrogen. c) i) The tendency of an atom to draw an electron density closer to itself in a covalent bond ii) LiF iii) I think it's H3B as it does say compound and H2 or F2 arent compounds, theyre elements
5. a) crude oil; fractional distillation b) c12h26 + 12.5 O2 --> 12CO + 13H2O c) i) High temperature from combustion of paraffin causes nitrogen in air to combust ii) 2NO + O2 --> 2NO2 iii) 4NO2 + O2 + 2H2O ---> 4HNO3 d) i) C n H 2n+2 ii) C12H26 --> C6H12 + C6H14 ; C3H7 ; zeolite/aluminosilicate/silicon/aluminium oxide iii) dodecane is bigger molecule so it has more electrons and more van der waals BETWEEN MOLECULES e) 2,2,3,3,4,4-hexamethylhexane ; chain f) Cl2
6. a) i) something like 1.28 molperdm3 or something i cant remember exactly ii) 71.5% (i did this wrong calculate Mr of calcium nitrate wrong so probably dropped 1 mark ) b) 3Ca(OH)2 + 2H3PO4 --> Ca3(PO4)2 + 6H2O c) empircal formula was Ca(H2PO4)2 and x=2
7. a) TlBr3 2- should be tetrahedral with Tl centre, electron density at top and Br on each other vertex. TlCl4 3- should be trigonal bipyramid with 4 Chlorine--Thallium bonds and 1 electron density
b) Ionic bonding; strong electrostatic attraction between oppositely charged IONS c) Tl (s) + 0.5 Br2 (g) --> TlBr (s) (not sure if state symbols required)
Hey, i got a U in my mock and i dont want a repeat of that in may sooo can anyone give me revsion tips?
I'll repeat what I said to someone else who said a similar thing:
Find out where you lost your marks and target the weaker points. Ask your teachers for any advice and practice as many questions as you possibly can between now and May.
Hey, i got a U in my mock and i dont want a repeat of that in may sooo can anyone give me revsion tips?
TSR has a lot of useful resources that will help you to get organised. eg the Study planner; make sure you're using it to help you organise Unit 2 revision and Unit 1 revision so that you're in tip form for the exam. Simply go over the content, reading the book and making notes and answering questions making sure you fully understand each topinc and I'm sure you'll be well on your way to an A (aswell as doing all the past papers before the exam)
& I got an A - 86% in my mock however Im really scared I will forget how to answer the harder set of questions when it comes to the real exam.
Have you dont your mock yet? & if so what did you get
TSR has a lot of useful resources that will help you to get organised. eg the Study planner; make sure you're using it to help you organise Unit 2 revision and Unit 1 revision so that you're in tip form for the exam. Simply go over the content, reading the book and making notes and answering questions making sure you fully understand each topinc and I'm sure you'll be well on your way to an A (aswell as doing all the past papers before the exam)
thanks alot! But say you did a past paper and you got a bad mark apart from looking at the mark scheme what do you do? Also this is going to sound dumb but how do you make notes for chem? do you know any useful websites?
thanks alot! But say you did a past paper and you got a bad mark apart from looking at the mark scheme what do you do? Also this is going to sound dumb but how do you make notes for chem? do you know any useful websites?
No problem & If you did a past paper, and it was marked and a bad score was achieved. Apart from looking at the mark scheme you can review the paper and use your textbook to review the questions you got wrong; reading the appropriate chapter and understanding what you have done wrong and how to do it better next time. Then reattempting the question. But it is inevitable you use the mark scheme to see ideally what the examiners want.
You make notes by simply reading the book. Read a paragraph and using the specification if needed pick out the key points from that paragraph and put it in your own words it helps you remember it. However get used to the terminology of the subject and adapt your "Own words" to be like that of the text book. With more practise you will become better at this. Also when reading the textbook if you come across any word or sentence you dont know the meaning of or do not understand, DO NOT move on until you fully understand it. Use the internet, dictionary etc to make sure you actually understand the meaning of what you are reading.
Ive mentioned some good websites for chemistry already at the top: there is also Bluecoatchemistry on youtube Tywin Lannister has some good videos for AS & A2 level chemistry. However the good old reading it yourself and understanding it is the best way to go.
Wow thats a good score, well done. How are you finding Unit 2
Thank you
I am quite enjoying unit 2 at the moment. I like Energetics and Kinetics but I'm struggling a bit with Equilibria. With my other teacher we've done Haloalkanes which isn't too bad, just the mechanisms are a pain to draw out to get full marks! How are you finding it?
I am quite enjoying unit 2 at the moment. I like Energetics and Kinetics but I'm struggling a bit with Equilibria. With my other teacher we've done Haloalkanes which isn't too bad, just the mechanisms are a pain to draw out to get full marks! How are you finding it?
I'm actually finding unit 2 pretty straight forward. We have done kinetics equilibrium and group 2 alkaline metals and extraction of metals