spectroscopy and analysis

Question 1

what is the frequency of an electromagnetic radiation?

Answer 1

cycles per second

Question 2

relationship between wavelength and frequency?

Answer 2

wavelength inversely proportional to frequency

Question 3

what is the speed of light in a vacuum?

Answer 3

3 × 10^8 ms^-1

Question 4

how to calculate speed of light?

Answer 4

c= wavelength * frequency

Question 5

what does a higher frequency on a visible colour spectrum mean?

Answer 5

the higher the frequency the shorter the wavelength
therefore the higher the energy

Question 6

what is the order of electromagnetic spectrum form higher to lower energy (shorter to longer wavelength)?

Answer 6

gamma, X-ray, UV, infra-red, microwave, radio

Question 7

what is the energy of photons given by?

Answer 7

E=hv
h is Planck’s constant

Question 8

what is the value of Planck’s constant?

Answer 8

6.626 × 10^-34 m^2 kg s−1

Question 9

what happens during spectroscopy?

Answer 9

EMR with specific frequency is absorbed by molecule which then becomes excited

Question 10

does electromagnetic radiation have a range of frequencies corresponding to what?

Answer 10

electronic transitions

Question 11

what happens to the electron after radiation is absorbed?

Answer 11

electron promoted to a higher level

Question 12

what is an orbital?

Answer 12

region of space that can hold a maximum of two electrons with opposite spins

Question 13

when will hydrogen atoms absorb photons?

Answer 13

hydrogen atoms will absorb photons with frequencies that agree with the differences between energy levels

Question 14

what is λmax?

Answer 14

wavelength of a sample that has the highest absorbance

Question 15

why are absorption broader as molecules become more complex?

Answer 15

more vibrations and rational energy levels

Question 16

what happens as conjugation increases?

Answer 16

gaps between HOMO and LUMO decreases

Question 17

difference between atomic and molecular absorption?

Answer 17

atoms have a sharp spectra
molecules have broad spectra

Question 18

what is transmission?

Answer 18

fraction of light intensity that has passed through a sample unchanged

Question 19

what is the equation of absorbance (A)?

Answer 19

A=-log T

Question 20

what is the equation of transmittance?

Answer 20

T= I/I0

Question 21

what is lamberts law?

Answer 21

A proportional the l
l (path length)

Question 22

what is the beer lamber law?

Answer 22

A is proportional to c
c (concentration)

Question 23

what is the beer lambert equation?

Answer 23

A= εcl

Question 24

what is molar extinction?

Answer 24

the absorbance of 1 mol dm-3 sample with path length of 1cm

Question 25

what layout does the beer lambert equation have?

Answer 25

A= εl * c y= m * x

Question 26

how can a bond be approximated?

Answer 26

spring between two spheres

Question 27

equation for wavenumber (ṽ)?

Answer 27

ṽ =1/λ

Question 28

what does a high wavenumber mean?

Answer 28

high frequency

Question 29

what does increasing bond strength between two spheres do?

Answer 29

increasing bond strength increases frequency

Question 30

what does decreasing size of spheres do?

Answer 30

increases frequency

Question 31

what are the two components of electromagnetic radiation?

Answer 31

magnetic field going in the x-axis electric field going in the y-axis

Question 32

what is a photon?

Answer 32

little packet of energy that goes in the same direction as light

Question 33

what is spectroscopy defintion?

Answer 33

'study of the interaction between electromagnetic radiation and matter'

Question 34

what is monochromator?

Answer 34

one colour with a specific wavelength that is split

Question 35

where are the electrons in an orbital

Answer 35

orbital is where 95% of the electrons will be found

Question 36

why are electrons further away from the nucleus harder to remove?

Answer 36

electrons further away form the nucleus are harder to remove because they're at a higher energy level

Answer 37

'the difference between energy in vibrational energy levels matches the infra-red part of the electromagnetic spectrum'

Question 38

what happens to a bond when it absorbs photons?

Answer 38

when bonds absorb photons its amplitude increases frequency remains the same

Question 39

what does doubling concentration do to absorbance?

Answer 39

doubling concentration doubles absorbance

Question 40

what is spectroscopy?

Answer 40

'The study of the interaction between electromagnetic radiation and matter.'

Question 41

THz to Hz?

Answer 41

1THz =1 *10^12 Hz

Question 42

GHz to Hz?

Answer 42

1GHz= 1 *10^9

Question 43

MHz to Hz?

Answer 43

1MHz= 1*10^6

Question 44

nm to m?

Answer 44

1nm = 1*10^-9 m

Question 45

pm to m?

Answer 45

1pm = 1*10^-12

Question 46

micrometer to cm?

Answer 46

1micrometer = 1*10^-4cm

Question 47

units of each component in beer-lambert law?

Answer 47

molar extinction = dm3 mol-1 cm-1 conc = mol dm-3 path length = cm

Question 48

what does decrease in electronegativity do to the vibrational frequency?

Answer 48

decrease