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    (Original post by esfio)
    Weren't the peaks at 158 and 162 ~75% and ~25%?
    I had three peaks. Two was 25% and one was 50%

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    Was the Mr question part of a titration table question or not?
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    6 marker on standard solution:
    1) weigh out a certain mass of MHCO3 using top pan balance and weighing boat
    2) dissolve in deionised/distilled water in a beaker and use glass rod to stir
    3)pour into 250cm3 volumetric flask (could use a glass funnel)
    4) rinse beaker and glass funnel a few times with distilled water and transfer to volumetric flask (maybe 3/4 times) to ensure all MHCO3 is transferred
    5) fill up to line with distilled water, making sure the bottom of the meniscus touches the line at eye level
    6) put lid on and secure, invert a few times to ensure all solute has dissolved
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    (Original post by Ilyas_99)
    6 marker on standard solution:
    1) weigh out a certain mass of MHCO3 using top pan balance and weighing boat
    2) dissolve in deionised/distilled water in a beaker and use glass rod to stir
    3)pour into 250cm3 volumetric flask (could use a glass funnel)
    4) rinse beaker and glass funnel a few times with distilled water and transfer to volumetric flask (maybe 3/4 times) to ensure all MHCO3 is transferred
    5) fill up to line with distilled water, making sure the bottom of the meniscus touches the line at eye level
    6) put lid on and secure, invert a few times to ensure all solute has dissolved
    I forgot how to do this. I did up to the third point. So annoyed with myself

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    (Original post by esfio)
    Weren't the peaks at 158 and 162 ~75% and ~25%?
    it said both isotpes wer equal
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    (Original post by Suffy)
    The first question is wrong. And so is the 3rd one. Surely the 4s subshells fills before the 3d one so its 4s1 3d2. Then the third one is Ca3P2. As you needed to get the ions and balance the charges.


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    I think you forget that transition metals lose their 4s electron before losing 3 d electron ?
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    (Original post by DaVinciGirl)
    I had three peaks. Two was 25% and one was 50%

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    Didn't the question say that there where only 2 isotopes of Bromine and they were both approximately equal in abundance?
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    (Original post by Huzaefah)
    Didn't the question say that there where only 2 isotopes of Bromine and they were both approximately equal in abundance?
    That's what I thought aswell!
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    (Original post by IntellectualBoss)
    bromine mass spectrum- 50% at 158 and 50% at 162
    The question stated they were [Br2]+ ions, so there were 2 Br in each ion, giving 3 different combinations, see the pic below. 25% 158, 25% 162, 50% 160.

    Name:  bromideion.PNG
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    (Original post by Huzaefah)
    Didn't the question say that there where only 2 isotopes of Bromine and they were both approximately equal in abundance?
    I just did what was in the text book. Not sure anymore

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    • Welcome Squad
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    Welcome Squad
    (Original post by DaVinciGirl)
    I think this was a question
    Mg2+ and Na+ which is has the smallest atomic radii?
    I wrote Mg as it has same shielding, and number of electrons but has more protons. So more nuclear attraction between electron and nucleus.

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    i forgot to write same shielding >,<
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    (Original post by DaVinciGirl)
    Chloride ions oxidation
    2Cl- -> Cl2 + 2e-


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    What did you get for the half equation with ClO- to produce chloride water or something ?
    And what was the overall equation that you got
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    (Original post by koolgurl14)
    i forgot to write same shielding >,<
    Not sure if that was as important to write. I'm sure you got the marks if you mentioned the other stuff

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    • Welcome Squad
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    Welcome Squad
    (Original post by DaVinciGirl)
    Not sure if that was as important to write. I'm sure you got the marks if you mentioned the other stuff

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    ya hopefully what did u get for the question where we had to calculate the velocity?
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    MCQ:
    balance- 4:7
    empirical of hydrocarbon- c3h8
    solution neutralised by sulphuric acid- 50cm3 of 1x10dm3
    mass of gold 19.3
    no2 was brown and forward exothermic
    reducing agent- crO7
    ionisation energy decreases down group 2
    ClF3 is most polar molecule
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    (Original post by DaVinciGirl)
    I think this was a question
    Mg2+ and Na+ which is has the smallest atomic radii?
    I wrote Mg as it has same shielding, and number of electrons but has more protons. So more nuclear attraction between electron and nucleus.

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    i forgot to write that it has more proton :'( thought i did ok but then realised i messed up on so many questions as i was discussing them with my friends.
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    (Original post by IntellectualBoss)
    MCQ:
    balance- 4:7
    empirical of hydrocarbon- c3h8
    solution neutralised by sulphuric acid- 50cm3 of 1x10dm3
    mass of gold 19.3
    no2 was brown and forward exothermic
    reducing agent- crO7
    ionisation energy decreases down group 2
    ClF3 is most polar molecule
    I thought the most polar molecule was BF3
    And I thought the reducing agent was C2O4
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    What did you guys get for Q9: I said the white precipitate was BaSO4 and that the percentage was 27.7%
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    (Original post by SargentZenj2)
    What did you guys get for Q9: I said the white precipitate was BaSO4 and that the percentage was 27.7%
    I got BaSO4 but I got something around 33.4%
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    Question about velocity of 52Cr+. Is V=1.714X10^6 ms^-1
 
 
 
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