INDIVIDUAL REFLECTION ON P1 AS PRELIMS by Pooganeswari Siteram Pillai https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz What are the important things that you have learnt from this paper? en-us 2021-09-08 00:37:50 UTC 2021-09-14 04:49:37 UTC hello@padlet.com Catherine JC2T https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723307008
  • isoelectronic: having same no. of electrons
  • square planar structure: 1lp 4bp
  • enthalpy of combustion of H2 is the enthalpy of formation for H2O
  • sulfur and phosphorus can form two acidic oxides (P4O10 and P4O6)
  • I2 is brown in solution form
  • going down the group, harder to decompose
  • metal oxide react with HCl to form salt and water (there is no effervescent)

    • ]]>     2021-09-08 01:07:58 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723307008     Jasmine JC2T https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723317220 Revised on :
    - free radical substitution 
    - reaction of carbonates and acids
    - isoelectronic -> same electron number
    - chiral centres
    - 1°, 2°, 3° halogenoalkanes
    - SN1 and SN2
    - bond angles and shapes
    - enthalpy change
    - boltzman distribution curve
    - AgBr, AgCl, AgI precipitate colors
    - electronegativity trends
    - test for carbonyl compounds]]>     2021-09-08 01:12:11 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723317220     Frederic https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723319439 In this AS prelim, i made a lot of careless mistakes because I either didn't fully read the question or I read the questions and answers to fast resulting in mistakes.
    -Isoelectronic means that elements have the same no of electrons
    -Phosphorus can form 2 oxides which are P4O6 and P5O10
    -Iodine is a brown liquid-gas in room temperature
    -Effervesence is connected to the gas produced
    -Reactions of halogenoalkanes

    ]]>     2021-09-08 01:13:03 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723319439     Michael jc2t https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723321511 Bromine is more reactive than iodine so displacement reaction will occur and the solution will become brown because I2 is brown in solution form. Dilute aqueous ammonia is not enough to dissolve AgBr so there will be a cream precipitate. Unsaturated means that the displayed formula must have double bond. Alcohol is neutral while carboxylic is acidic. Chiral centre means the carbon must have four different groups. Delta positive and delta negative will interact because they are polar so there will be permanent dipole interaction. All molecules will have van Der Waals forces so there will be temporary dipole-induced dipole interaction. As we go down the group, more heat will be needed for thermal decomposition so SrCO3 will not decompose.]]> 2021-09-08 01:13:51 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723321511 Christopher JC2T https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723358608 I revised about:
    - The colors of halogens in different forms (aqueous, gaseous)
    - The features of Infra-Red Spectroscopy.
    - The trends of Group 2 metals and their compounds. 
    - Isomers]]>     2021-09-08 01:26:54 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723358608     Jacksen JC2T https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723363202 - careless mistake (both theory and calculation)
    - lack of understanding  for equilibrium chapters (calculation) 
    - Lack of understanding for enthalpy chapter 
    - isoelectronic 
    -isomerism need practice 
    -polymerization need more practice

    ]]>     2021-09-08 01:28:32 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723363202     Josh JC2T https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723367293 - Isoelectronic is the same number of electrons.
    - 1 lone pair and 4 bonding pairs is square planar.
    - 6 bonding pairs is octahedral
    - Need to be more careful on oxidation number calculation
    - Group 2 metals when reacting with water will form a hydroxide and hydrogen gas such that a gas is produced.
    - SrCO3 does not decompose from heat.
    - BaCO3 is difficult to decompose.
    - Metal oxides react with aqueous hydrochloric acid to form salt and water such that there is effervescence.

    ]]>     2021-09-08 01:30:02 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723367293     Elizabeth Donna JC2T https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723368808 P1 Reflection 
     - primary -> Sn2
     - Electronegativity : attracting electrons in covalent compounds 
     - Carboxylic acid from nitrile 
     *RCN + HCl (aq) + H2O --> RCOOH + NH4Cl

    ]]>     2021-09-08 01:30:35 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723368808     Sharon JC2T https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723370800 reflection
    1. ionisation energy is always endothermic (delta H = positive value)
    2. isoelectronic is elements having the same no. of electrons
    3. across periodic table, radius is getting smaller (nuclear attraction is more)
    4. metalling bonding (bond between ions and delocalised electrons)
    5. square planar structure = 4 bp, 2 lp
    6. octahedral = 6 bp
    7. ideal gas = high temperature and low pressure 
    8. enthalpy change of atomisation is always positive, neutralisation is negative, formation can be both, ionisation energy is positive, solution can be both, combustion is negative, hydration is negative
    9. Kc and Kp is only affected by temperature
    10. Kc = ignore (s)/solid
    11. Boltzmann curve = higher temperature, peak lower and go to the right
    12. SiO2 insoluble in water
    13. cream precipitate (silver nitrate) —> bromide ions, white precipitate (silver nitrate) —>  chloride ions, yellow precipitate (silver nitrate) —> iodide ions
    14. unsaturated (C = C)
    15. chiral centre (carbon bonded with 4 different groups)
    16. Sn2 (formation of intermediate)
    17. tri-iodomethane (methyl ketones, ethanal, alcohol with CH3 group)
    18. LCP principle, equilibrium shifts to the direction that reduces the change
    19. carbonates decompose into oxides and carbon dioxide
    20. Cl2 is more reactive than I2 (form equilibrium)
    -- avoid careless mistakes
    ]]>     2021-09-08 01:31:19 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723370800     MichelleV Jc2T https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723375413 i made some silly mistakes in this prelims as for simple questions like number 1. 
    Things i revised on the video:
    - Sterioisomers
    - Halogenoalkanes
    - How to count for chiral centres
    - What isoelectric means
    - Different bond angles and their structures (square planar especially)
    - some enthalpy change will only be positive, negative or both
    - going down the group, need more heat energy
    - boltzmann curve

    ]]>     2021-09-08 01:32:44 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723375413     Arwen_JC2 T https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723379701 information to revise:
    • isoelectronic - no. of electrons the same
    • smaller size of atoms; stronger attraction to nucleus
    • atomisation - bond breaking; always +; IE - supplying energy; always + // formation can be + or -
    • poisonous gases - sulfur (SO2), ethane, nitrogen
    • acidic bond - carboxyl
    • SN2 - NO CARBOCATION! forms intermediate
    • triiodomethane - alcohol (OH group, H group, CH3, any R group) // aldehyde or ketone (CH3 and R group)
    • smiling ghost alcohol
    • only aldehyde can give positive reaction w tollen and fehling
    • "which of following quantities is equal to avogrado constant" - use 1 mole not 6.02x10^23...
    • polar is definitely permanent dipole-dipole
    • go down group, thermal decomposition more difficult (higher energy and temp. needed)
    • non-metals reactivity - ability to gain electron; H2 and I2 form equilibrium

    answering exams:
    • when drawing, start with the easier molecules
    ]]>     2021-09-08 01:34:17 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723379701     Benedict JC2T https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723381572 -Isoelectronic means that t has the same number of electrons
    - phosphorus can form it's 2 oxides, P4O6 and P5O10
    - 6 bonding pairs make up an octahedral
    - Across a period, the ionic radius becomes smaller
    - Going down the group, more heat is needed for thermal decomposition

    In this prelim, i made alot of careless mistakes and just didn't know some questions in general. I need to memorize more reactions and conditions.]]>     2021-09-08 01:34:57 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723381572     Nicholas JC2 Truth https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723409596 I need to read carefully and revise on the reactions of G2, 17 and period 3. I learnt about:
    - isoelectronic, elements with the same number of electrons
    - iodine is brown in liquid form, purple in gaseous state, black in solid form
    - having a C=C bond does not always mean that it has a cis/trans isomer but it is still counted as 1 stereoisomer]]>     2021-09-08 01:45:05 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723409596     Davis JC2Grace https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723791723 In this paper, I made a careless mistake regarding isomerism. 
    I learnt about  th reaction of halogenoalkene with excess ethanolic sodium hydroxide.

    I need to practice and review for the calculations.]]>     2021-09-08 04:18:32 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723791723     Keira JC 2 Grace https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723918844 - isoelectronic : same number of electrons
    - square planar structure : 4bp, 2lp
    - radius of an atom gets smaller across the periodic table therefore nuclear attraction increases
    - Kc and Kp is only affected by temperature
    - boltzmann curve : higher temperate = lower peak, shift to the right
    - AgCl : white, AgBr : cream, AgI : yellow
    - chiral center : carbon having 4 different groups
    - SN2 does not form carbocation, only intermediate

    I need to practice more on the calculations for number of moles and counting the number of stereoisomerism that can be formed from a compound.]]>     2021-09-08 05:25:26 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1723918844     Nevan https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1724053860 Found out i was weak in periodicity and trends of thermal stability and reactivity]]> 2021-09-08 06:36:12 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1724053860 Jonathan https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1724172694 Overall I felt that the paper was okay, but for some questions the instructions need to be read more carefully as some important information may be mentioned that was skipped.]]> 2021-09-08 07:34:14 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1724172694 Ella Suita JC2 Grace https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1724177020 I have learnt to pay more attention to the wording of the questions and consider all possible alternatives. Furthermore, I have realised the importance of reading through the options I deem incorrect and be able to prove why it is so. The most important of all, in my opinion, is to commit all concepts to memory in order to ensure that I do not overlook any steps in my working when answering the questions.]]> 2021-09-08 07:36:25 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1724177020 Geoffrey Jc2Truth https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1724266305 In the discussion revised about the 
    -Chiral Centers 
    -The term Isoelectronic 
    -Periodicity
    -Sn1 and Sn2 
    -Free Radical Subsitutions
    -Enthalphy changes reactions and computations

    In this paper i did a lot of mistakes due to not reading more and need to put in more time in revising the topics ]]>     2021-09-08 08:23:28 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1724266305     Kevin B https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1724271478 I  revised about the AgBr, AgCl, AgI precipitate, some group 2 carbonates and nitrates such as Ba,Sr  need higher energy to decompose, bond angles and shapes, and electrongativity trends across period and down the group.

    ]]>     2021-09-08 08:26:08 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1724271478     michelle jc 2 grace https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1724539552 the questions in this paper was okay except i made some mistakes with the calculation and i need to revise more on structures and the substitution of mechanisms and learn to analyze the drawings more. i also need to remember the colour of certain compounds and memorize them carefully. overall i need to understand and memorize certain topics more thoroughly especially the drawings of mechanisms and memorizing the colours.]]> 2021-09-08 11:08:48 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1724539552 Dylan JC2 Grace https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1724546908 From the P1 AS Prelims, one of the most important things I learnt is about how stereoisomerism can be formed — for example, in No. 26, I learnt how many different hydrocarbons can be produced when 3-bromo-3-methylpentane reacts with excess ethanolic sodium hydroxide.

    Overall, I also learnt that it is important to take note of the time especially in Paper 1, so I would be able to have more time to go through my answers and not make any careless mistakes, just like in No. 35 where I didn't analyze the statements regarding hydrogen halides properly.

    After the Prelims, I more or less know what are my strengths and weaknesses — and know what I should focus on more in preparation for the future ALevel Exams, and how to improve from my past mistakes.]]>     2021-09-08 11:13:45 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1724546908     Wilson https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1724742556 I learnt that mastering the concept is not enough, you must also be careful when doing the questions. In this paper I learnt about the shape of BF4- has a square planar structure. I also learnt about the trends in both Group 2 and Group 7 which are quite puzzling at times. Furthermore, I need to be more careful when counting the number of stereoisomers and positional isomers there are.]]> 2021-09-08 12:54:23 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1724742556 Angela jc2g https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1724746531 From this prelims paper, I learned that I should understand and memorize concepts such as trends better, read questions more thoroughly, manage time better so I can recheck my answers and avoid careless mistakes, practice and do more questions, revise topics in depth. ]]> 2021-09-08 12:55:51 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1724746531 Jennifer JC2G https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1724749043 The questions that involved Br were merciful. I need to revise more on questions with diagrams.]]> 2021-09-08 12:56:47 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1724749043 Ashley JC2 Grace https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1724928185 From the P1 Chemistry Prelims, I definitely need to learn more of the nuanced / detailed section of the syllabus T^T. Polymer interaction, isomers (and counting them), group 2 carbonates and their reactivity, and their electronegativity trends are some of my weak points shown from P1. ]]> 2021-09-08 13:50:59 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1724928185 Earlene JC2G https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1724946093 Through the Chemistry AS Prelim P1, I realised that I have many careless mistakes that cost me a lot of marks. I need to be more careful when answering the questions and I need to practice more so that I will be able to answer at a faster pace. Overall, I feel that I have a rough idea of the topics being taught but my knowledge is still insufficient to say that I have a good grasp of the subject, therefore I will revise more on the topics to be better at tackling the different types of questions, even those that are not within the syllabus. I realised that I had difficulties applying what I have learnt as I relied heavily on memorisation instead of understanding and mastering the topic.


    Through this test, I have learnt/revised the following:

    1. Enthalpy of atomisation and enthalpy of ionisation are always endothermic.

    2. Phosphorus can form P4O10 or P4O6

    3. Carbonates become more thermally stable going down group 2 (ex: SrCO3, BaCO3).]]>     2021-09-08 13:56:20 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1724946093     Audrey JC2T https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1727249816 I learnt about the graphs of period 3, how to identify stereoisomers and structural isomers, propagation reaction of halides. I had to recheck and found some careless mistakes which I should pay more attention to in the future. ]]> 2021-09-09 06:48:39 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1727249816 Thomson https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1730533100 Revise on which is cis and which is trans, periodicity and catlyst along with conditions for reactions]]> 2021-09-10 09:52:30 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1730533100 Josh JC2G https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1730652898 From reviewing the video, Ive highlighted my weakpoints, of which are
    : Careless mistakes
    : Counting isomers
    : The disproportionation reactions of Chlorine with sodium hydroxide]]>     2021-09-10 11:34:55 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1730652898     Lindsay JC2G mwm6s5yc99 https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1733669866 Doing this paper, I realised I did not revise enough and tend to spend time recalling for information that I should have recalled right away. I tend to not have enough time for the paper and therfore not enough time to chdck.]]> 2021-09-12 13:25:53 UTC https://padlet.com/pooganeswaripiks/b18y8lkki6snkdxz/wish/1733669866