Exam (elaborations)
Edexcel A-Level Chemistry: Topic 19 Complete exam 100% Correctly solved
- Module
- Edexcel A-Level Chemistry
- Institution
- Edexcel A-Level Chemistry
Edexcel A-Level Chemistry: Topic 19 Complete exam 100% Correctly solved
[Show more]
Content preview
Edexcel A-Level Chemistry: Topic 19Complete exam 100% Correctly solved
When is a molecular ion formed? - Answer>>When a molecule
lose an electron
What is very accurate mass spectrometry called? -
Answer>>high resolution mass spectrometry
Why is high resolution mass spectrometry better than normal
mass spectrometry. - Answer>>identify compounds which have
m/z values that round to same nearest whole number
What is NMR for - Answer>>Finding the structure of organic
molecules
What are the 2 types of NMR - Answer>>Carbon 13 NMR High
resolution proton NMR
Explain how NMR works in 3 steps - Answer>>Sample under
strong magnetic field - exposed to different fequencies of
radiwaves
Nuclei absorb diffent amounts of energy because of their
environment
pattern of absorption shows where some atoms are in a molecule
and how many of them their are
What does Carbon 13 NMR show? - Answer>>Number of
carbon atoms and environments they are in
What does high-res proton NMR show - Answer>>number of
protons/hydrogen and environments they are in
, What is meant by an environment in NMR - Answer>>Amount
of electron shielding given by its electrons and the surrounding
molecules
How does the environment affect NMR - Answer>>Nuclei have
different magnetic field in different environment
So absorb different amounts of energy at different frequencies
What are the 3 steps to interpreting a carbon-13 NMR spectra -
Answer>>Count the number of carbon environments (each
peak = 1) (except the peak at 0 which is TMS)
Look at chemical shifts and match to peaks/environments
Try out different possible molecules
Why do peaks in proton NMR spectra split? - Answer>>Only
peaks of those attached to Carbon split
Splitting is caused by hydrogens on adjacent carbon atoms, this is
called *spin-spin coupling*
What are the split peaks on proton NMR spectra called -
Answer>>Multiplets
How do you determine how many a peak will split into in proton
NMR spectra? - Answer>>n+1 rule count number of hydrogen
on adjacent carbons, add 1 and this is amount of new peaks
What does the area of under proton NMR show you? -
Answer>>Relative area shows relative amount of hydrogen in
each environment
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller RevisionKing. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £5.76. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
76449 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy revision notes and other study material for 14 years now