Elements Of Life: Spectroscopy

Question 1

What is the order of the EM spectrum with increasing frequency?

Answer 1

Radio, Micro, IR, Light, UV, X, Gamma

Question 2

What is the order of the EM spectrum with increasing wavelength?

Answer 2

Gamma, X, UV, Light, IR, Micro, Radio

Question 3

What is the order of the EM spectrum with increasing energy?

Answer 3

Radio, Micro, IR, Light, UV, X, Gamma

Question 4

Which EM wave has the longest wavelength

Answer 4

Radio

Question 5

Which EM wave has the shortest wavelength

Answer 5

Gamma

Question 6

Which EM wave has the highest frequency

Answer 6

Gamma

Question 7

Which EM wave has the lowest frequency

Answer 7

Radio

Question 8

Which EM wave has the highest energy

Answer 8

Gamma

Question 9

Which EM wave has the lowest energy

Answer 9

Radio

Question 10

Definition of quantisation

Answer 10

Specific energy value

Question 11

Name 2 types of spectra

Answer 11

Absorption

Emission

Question 12

What does energy absorbed by an electron do

Answer 12

Causes electrons to be excited = promote ( jump ) to higher energy levels

Question 13

When electrons are excited state what does this result in

Answer 13

(Atom) = unstable

Question 14

When electrons are in excited states ( unstable ) what do they do

Answer 14

Electrons drop back down = emitting photo ( light )

Question 15

What does energy levels being quantised ( having a specific energy value ) result in

Answer 15

Lines of specific frequencies / wavelengths

E = hv

Question 16

List similarities between the 2 types of spectra (2)

Answer 16

1. Lines in both = closer together at high frequencies
2. Both are LINE spectra
   • E=hv
   • lines of specific frequencies

Question 17

List differences between the 2 spectra

Answer 17

1. Absorption = coloured back ground - Emission = black background

Question 18

What do energy absorbed and energy emitted always have to be

Answer 18

The exact same

Energy absorbed = energy emitted

Question 19

What is the 6 marker answer need to learn for line spectra questions

Answer 19

1. Energy absorbed causes electrons to be excited
2. = promotion ( jump ) to higher energy levels
3. Excited states = unstable = electrons drop back down emoting photon ( light )
4. Energy levels = quantised ( specific energy value )
5. = lines of specific frequencies / wavelengths
6. E = hv
7. Draw diagrams

Question 20

Equation for c, speed of light

Answer 20

c=v lamda

Speed of light = frequency x wavelength ( m )

Question 21

1st equation for E, energy ( J )

Answer 21

E=hv

Energy = planks constant x frequency

Question 22

2nd equation for E, energy ( J ) when only given the wavelength

Answer 22

E= hc/ lamda

Energy (J) = ( planks constant x speed of light ) / wavelength

Question 23

How to go from J -> KJmol^-1

Answer 23

Divide by 1000
Then…
Multiply by Avogadros constant

Question 24

How to go from KJmol^-1 -> J

Answer 24

Divide by Avogadros constant
Then….
Multiply by 1000

Question 25

What does ‘c’ stand for

Answer 25

Speed of light

Question 26

What does ‘h’ stand for

Answer 26

Planks constant

Question 27

Describe emission spectra

Answer 27

1. Coloured lines on black background
2. Lines = specific to an element
3. Because energy gaps = unique
4. Compare with known data

Question 28

How lines used to identify elements

Answer 28

1. Each element = own specific energy level
2. = Different energy gaps
3. = Different frequency lines
4. Compare frequencies of lines with known data

Question 29

How lines formed + why they have specific frequencies

Answer 29

1. Atoms absorb energy
2. Electrons promote to higher energy level
3. Atom = unstable = electrons drop back down emitting light
4. E=hv ( energy dropped = proportional to frequency )