AS Chemistry- helping each other out!
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Hi guys, Just wondering. For OCR F321, does OCR have a preference for continuous prose in the longer 5/6 mark questions (such as the periodic trends stuff) or are bullet point answers fine? Don't want to lose marks by not writing in the correct style but I prefer bullet points because I find them quicker to write out.
Hi guys, Just wondering. For OCR F321, does OCR have a preference for continuous prose in the longer 5/6 mark questions (such as the periodic trends stuff) or are bullet point answers fine? Don't want to lose marks by not writing in the correct style but I prefer bullet points because I find them quicker to write out.
Hi could someone explain how you do this please? Thank you 
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Original post by TeaAndTextbooks
What exam board? Never seen this type of Q before.
Original post by TeaAndTextbooks
1ppm=1*10^-6
33ppm=33*10^-6 multiply this by 1000g (1kg)
It's similar to percentage. If you were told 20% of a kilogram of a mixture is X, to get x you would multiply a kilogram by 0.2
Percentage is 10^-2
Ppm is 10^-6 that's the only difference
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(edited 8 years ago)
Original post by _NMcC_
Posted from TSR Mobile
Hi guys, Just wondering. For OCR F321, does OCR have a preference for continuous prose in the longer 5/6 mark questions (such as the periodic trends stuff) or are bullet point answers fine? Don't want to lose marks by not writing in the correct style but I prefer bullet points because I find them quicker to write out.
Hi guys, Just wondering. For OCR F321, does OCR have a preference for continuous prose in the longer 5/6 mark questions (such as the periodic trends stuff) or are bullet point answers fine? Don't want to lose marks by not writing in the correct style but I prefer bullet points because I find them quicker to write out.
Bullet points are fine. Just make sure they are sentences.
Example:
There are a lot of van der waals forces.
More energy will be required to break these van der waals forces.
So 'inserthere' will have a higher boiling point.
Instead of
van der waals forces=more energy, so high BP.
Common sense really
.
Can some tell me what the equation is to work out ISOTOPIC ABUNDANCE ?????
Original post by TheNoobishKnight
Bullet points are fine. Just make sure they are sentences.
Example:
There are a lot of van der waals forces.
More energy will be required to break these van der waals forces.
So 'inserthere' will have a higher boiling point.
Instead of
van der waals forces=more energy, so high BP.
Common sense really.
Example:
There are a lot of van der waals forces.
More energy will be required to break these van der waals forces.
So 'inserthere' will have a higher boiling point.
Instead of
van der waals forces=more energy, so high BP.
Common sense really
.Thanks, Yeah it's not really hard material to understand. You just gotta learn the facts that explain the properties and be able include them them in the answers.
Cheers.
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Original post by FREYA2898
Can some tell me what the equation is to work out ISOTOPIC ABUNDANCE ?????
Well the equation to calculate relative atomic mass is this
And you can substitute values in to if you are given info and you can do the maths to find unknown
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Original post by C0balt
Well the equation to calculate relative atomic mass is this
And you can substitute values in to if you are given info and you can do the maths to find unknown
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And you can substitute values in to if you are given info and you can do the maths to find unknown
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Not necessarily over a 100 tho
Original post by frozo123
Not necessarily over a 100 tho
If percentage abundance given then it is
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Original post by TeaAndTextbooks
use this formula so you don't have to think about it
ppm= mass of solute/solution (in grams) x1000,000
Original post by C0balt
well yes, however if relative abundance y'know what to do
Original post by C0balt
Well the equation to calculate relative atomic mass is this
And you can substitute values in to if you are given info and you can do the maths to find unknown
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And you can substitute values in to if you are given info and you can do the maths to find unknown
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Hi this is correct if the abundance is a percentage divide by 100 but if it's not a percentage divide by the total abundance
Original post by samwillettsxxx
Hi this is correct if the abundance is a percentage divide by 100 but if it's not a percentage divide by the total abundance
Well I meant percentage as you can see from the triple %
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Original post by C0balt
1ppm=1*10^-6
33ppm=33*10^-6 multiply this by 1000g (1kg)
It's similar to percentage. If you were told 20% of a kilogram of a mixture is X, to get x you would multiply a kilogram by 0.2
Percentage is 10^-2
Ppm is 10^-6 that's the only difference
Posted from TSR Mobile
33ppm=33*10^-6 multiply this by 1000g (1kg)
It's similar to percentage. If you were told 20% of a kilogram of a mixture is X, to get x you would multiply a kilogram by 0.2
Percentage is 10^-2
Ppm is 10^-6 that's the only difference
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Thanks, that's what I did
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Enthalpy of combustion is reactants - products. I remember it as crp for combustion and fpr for formation. Crp is combustion reactants - products btw.
Original post by polar0id
Enthalpy change of combustion = {DeltaH products} - {DeltaH reactants}
How do you know if something has dipole dipole intermolecular forces? Is it when there's a large electronegativity difference
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.
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
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Admittedly the multiple choice is hard to mark because they are so packed
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LOOL whoops, yeah the answer is D.. nevertheless, thanks for the informative facts on IR spec!
(edited 8 years ago)
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.
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
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