inorganic chem flash - pink (use written notes)

Question 1

What is infrared spectroscopy used for

Answer 1

It’s used to identify specific functional groups in organic molecules

Question 2

Explain how infrared spectroscopy works

Answer 2

Infrared spectroscopy intakes infrared at organic molecules which causes their bonds to vibrate in different ways. The wavelengths which are absorbed depend on the type of chemical bonding the atoms at the end of these bonds

Question 3

What is the general rule regarding the weight of atoms and bond strength

Answer 3

Lighter atoms are converted by stronger bonds (higher energy radiation absorbed), heavier atoms are connected by weaker bonds (lower energy radiation absorbed)

Question 4

What is nass spectroscopy used for

Answer 4

Mass spectroscopy is used to determine the accurate molecular mass and structural features of a compound

Question 5

How does mass spectroscopy work

Answer 5

A small sample of an organic compound is bombarded by high energy electrons. This removes electrons from the organic molecule generating positively charged molecular ions known as parent ions. These molecular ions then break into smaller positively charged ion fragments

Question 6

Explain how proton nmr spectroscopy works

Answer 6

Nuclei of atoms behave like tiny magnets and in a strong magnetic field some align with the field (lower energy) whilst the rest align against it (higher energy). The absorption of radiation in the radio frequency of the electromagnetic spectrum causes the 1h nuclei to flip from the lower to higher energy alignment. As they fall back from higher to lower energy alignment emitted radiation is detected and plotted on a spectrum

Question 7

How are proton environments identified

Answer 7

The fragments

Question 8

empirical formula

Answer 8

practice this now

Question 9

Infrared spectroscopy can identify certain functional groups in an organic compound

Answer 9

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Question 10

When infrared radiation is absorbed by organic compounds, bonds within molecules vibrate (stretch and bend). The wavelengths of infrared radiations that are absorbed depend on the type of atoms that make up the bond and the strength of the bond.

Answer 10

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Question 11

Infrared measured in cm-1 wavelength

Answer 11

practice converting from wavelength cm-1 now

Question 12

practice converting from wavelength cm-1 now

Answer 12

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Question 13

Proton nmr spectroscopy can give information about different hydrogen atom environments, it can also measure how many hydrogen atoms are in these environments.

Answer 13

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Question 14

In the H1 NMR spectrum the chemical shift/peak position is related to the environment of the H1 atom. This is measured in parts per million (ppm)

Answer 14

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Question 15

The area under the peak is related to the number of 1H atoms in that environment and is often given by an integration curve on a spectrum.

Answer 15

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Question 16

Nmr spectra can be obtained using high or low resolution NMR

Answer 16

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Question 17

High resolution nmr uses higher radio frequencies than those used in low resolution nmr and provides more detailed spectra.

Answer 17

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Question 18

In high resolution proton nmr an interaction with 1H atoms on neighbouring carbon atoms will determine the number of peaks within a multiplet and can be determined using the N+1 rule, where n is the number of 1H atoms on the neighbouring carbon atoms

Answer 18

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Question 19

Low spectrum nmr can be sketched

Answer 19

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