Join TSR now and get all your revision questions answeredSign up now
    Offline

    2
    ReputationRep:
    How do you know if something has dipole dipole intermolecular forces? Is it when there's a large electronegativity difference
    Offline

    3
    ReputationRep:
    (Original post by Signorina)
    How do you know if something has dipole dipole intermolecular forces? Is it when there's a large electronegativity difference
    If the molecule is polar.
    That is when there's an electronegativity difference and when the centres of positive charge and negative charge do not coincide.
    Offline

    2
    ReputationRep:
    (Original post by C0balt)
    I guess she has mistaken it with other question
    Admittedly the multiple choice is hard to mark because they are so packed :lol:


    Posted from TSR Mobile
    LOOL whoops, yeah the answer is D.. nevertheless, thanks for the informative facts on IR spec!
    Offline

    2
    ReputationRep:
    (Original post by C0balt)
    If the molecule is polar.
    That is when there's an electronegativity difference and when the centres of positive charge and negative charge do not coincide.
    is dipole dipole interactions the same as permanent dipole interactions? because I know that ketones have permanent dipole interactions and CH3Cl, but the overall ketone molecule is not polar
    Offline

    2
    ReputationRep:
    (Original post by C0balt)
    Fingerprint region is the region on the right hand side of the spectrum with so many complicated peaks and they are completely different for every compound so can be used to distinguish two compounds like butan-1-ol and butan-2-ol. They will have similar pattern on the left but completely different on the right.

    So the two compounds in this question will have different fingerprint region.
    The answer is A because the C=O peak is different in aldehyde and ketone I guess?

    WAIT
    don't they have same molecular ion peak in mass spectra? Are you sure it's not D
    Posted from TSR Mobile
    if they both have an Mr of 58, why is their molecular ion peak different? is it because it is talking about the FRAGMENTS that they produce? in that case, I understand, but the multiple choice option says 'different MOLECULAR ion peaks at different m/e ratios' so surely, if they're talking about FRAGMENTS they wouldnt incude the word MOLECULAR ION PEAK? as this implies its the total Mr of the molecules, the peak furthest to the right on the x-axis...
    Offline

    3
    ReputationRep:
    (Original post by annie79)
    if they both have an Mr of 58, why is their molecular ion peak different? is it because it is talking about the FRAGMENTS that they produce? in that case, I understand, but the multiple choice option says 'different MOLECULAR ion peaks at different m/e ratios' so surely, if they're talking about FRAGMENTS they wouldnt incude the word MOLECULAR ION PEAK? as this implies its the total Mr of the molecules, the peak furthest to the right on the x-axis...
    Molecular ion peak is the same!!
    Offline

    2
    ReputationRep:
    (Original post by C0balt)
    If the molecule is polar.
    That is when there's an electronegativity difference and when the centres of positive charge and negative charge do not coincide.
    Thank you!
    Also, how is boiling pt and melting pt different ???
    on a past paper it says graphite has a high melting pt because of the covalent bonds. but iodine has a low boiling point because of vdw forces...
    so does boiling pt depend on intermolecular forces and melting pt depend on chemical bonds?
    Offline

    3
    ReputationRep:
    (Original post by Signorina)
    Thank you!
    Also, how is boiling pt and melting pt different ???
    on a past paper it says graphite has a high melting pt because of the covalent bonds. but iodine has a low boiling point because of vdw forces...
    so does boiling pt depend on intermolecular forces and melting pt depend on chemical bonds?
    They aren't any different. They depend on the forces of attraction between atoms/molecule /ions involved. Take silicon. The atoms are bonded covalently to neighbouring atoms so melting point is very high, and so is the boiling point
    Offline

    3
    ReputationRep:
    (Original post by annie79)
    is dipole dipole interactions the same as permanent dipole interactions? because I know that ketones have permanent dipole interactions and CH3Cl, but the overall ketone molecule is not polar
    Yes it is
    Ketone is polar
    Offline

    2
    ReputationRep:
    (Original post by C0balt)
    Molecular ion peak is the same!!
    Oh yeah! It asks for the INCORRECT one, sorry, had a blonde moment x_x
    Offline

    2
    ReputationRep:
    Can anyone help me with the extraction of tungsten the equation I need to know and the conditions and the risk? Please


    Posted from TSR Mobile
    Offline

    2
    ReputationRep:
    (Original post by c0balt)
    they aren't any different. They depend on the forces of attraction between atoms/molecule /ions involved. Take silicon. The atoms are bonded covalently to neighbouring atoms so melting point is very high, and so is the boiling point
    thank you!
    Offline

    8
    ReputationRep:
    Hello,

    Could someone please show me how to do this question (F321)? Parts ii) and iii) http://gyazo.com/e19a53c6d9c7727fbbf4b1786e71f885
    From January 2007 paper ( http://pastpapers.org/AS/chemistry/F...7_Jan_2811.pdf )

    Thanks
    Offline

    3
    ReputationRep:
    (Original post by itsConnor_)
    Hello,

    Could someone please show me how to do this question (F321)? Parts ii) and iii) http://gyazo.com/e19a53c6d9c7727fbbf4b1786e71f885
    From January 2007 paper ( http://pastpapers.org/AS/chemistry/F...7_Jan_2811.pdf )

    Thanks
    One Ca(OH)2 consists of three ions; Ca2+, OH- and another OH-. So in a mole of Ca(OH)2 there are three moles of ions.
    How many electrons are there in one ion of OH-? 8+1 for oxygen and hydrogen, and another for the negative charge so 10. So in a mole of OH- ion there are ten moles of electrons
    Offline

    3
    ReputationRep:
    (Original post by cheeky 12)
    Can anyone help me with the extraction of tungsten the equation I need to know and the conditions and the risk? Please


    Posted from TSR Mobile

    Hi tungsten is extracted using hydrogen. It can be extracted from its oxides with C however the product will be impure and brittle.
    WO + 3H2 ----> W + 3H2O
    hydrogen is expensive but you get pure tungsten
    Hydrogen is explosive when mixed with air
    Occurs at temperatures 700 celcius +
    Offline

    2
    ReputationRep:
    done a few AQA unit 2 past papers and I keep getting mid 80s, I need to get high 80s or above (need 121 ums) to get an overall A!!!!!! Grrrrrr
    Offline

    3
    ReputationRep:
    (Original post by NutE)
    done a few AQA unit 2 past papers and I keep getting mid 80s, I need to get high 80s or above (need 121 ums) to get an overall A!!!!!! Grrrrrr
    Me too lol keep getting 83.. Don't the grade boundaries change each year?
    Offline

    2
    ReputationRep:
    (Original post by samwillettsxxx)
    Me too lol keep getting 83.. Don't the grade boundaries change each year?
    83 is an A in the past papers, i'm sure. Well done yeah grade boundaries change every year, but if I get at least 88 then I know I've definitely got the 121 UMS i need. I'm actually aiming to get in the 90s but so far, no luck! I got 233 ums last year, so 7 away from an A!
    Offline

    0
    ReputationRep:
    When they say a chemical Is insouble, for Example BaSO4, does that mean it is insouble in any solution, say if it was Added to HCL or H2SO4.

    If something is insoluble, when added to solution, what happens, does it just not react? Nothing happens visibly or is a precipitate formed?

    Also what method could you used to determine a solubility of a Substance?
    Offline

    3
    ReputationRep:
    NEED HELP WITH THIS:
    2.4) What is the maximum mass of iron (III) chloride that can be produced from 50.0 g of Fe and 100gof chlorine gas ?2 Fe + 3 Cl2 → 2 FeCl3
 
 
 
Poll
If you won £30,000, which of these would you spend it on?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Quick reply
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.