1.3 (pt2)

Question 1

Avogadro’s law applies to…

Answer 1

only gases or liquid that’s formed as steam

Question 2

STP

Answer 2

0 degrees
1 atm pressure
molar volume = 22.4 dm3

Question 3

RTP

Answer 3

25 degrees
1 atm pressure
molar volume = 24.5 dm3

Question 4

Equation to work out number of moles of gas

Answer 4

n = V0 (volume of gas)
Vm (molar volume)

Question 5

Ratio e.e 3:2

Answer 5

rhannu gyda 3, lluosi 2

Question 6

Gas equation

Answer 6

pV=nRT
Mr

p=pascals
V=volume M3
R=gas constant (on data sheet)
T= Kelvin temperature (if indegrees +273)

Question 7

Reorganising the gas equation

Answer 7

pV=nRT
n=pxv/RT
V=nRT/p

Question 8

Mass Spectrometer

Answer 8

used to calculate the Mr of an element

Question 9

Mass Spectrometry theory

Answer 9

> Knowing the speed and force you can calculate mass - less the deflection, the heavier the object

Question 10

Full diagram of a mass spectrometer

Answer 10

.

Question 11

5 main stages of the mass spectrometer

Answer 11

1. Vapourisation
2. Ionisation
3. Acceleration
4. Deflection

Question 12

Vapourisation

Answer 12

Gases, liquids, volatile solids injected into the instrument.

volatile solids must be pre-heated to vaporise them.

Question 13

Ionisation

Answer 13

Vapourised sample passed into ionisation chamber.
>atom are bombarded with high energy electrons.
>some collision energetic enough to remove 1 or more electrons to make positive ions.

M(g) + e- –> M+(g) + e- +e-

Question 14

Acceleration

Answer 14

+ions are accelerated so they have the same kinetic energy.
+ions pass through three slits.

Question 15

Deflection

Answer 15

+ions enter the analyser tube (curved, surrounded by a powerful electromagnet)
>evacuated to a high vaccum so +ions don’t collide with background gas molecules.

Question 16

Amount of deflection depends on :

Answer 16

mass of object - lighter ions are deflected more
charge of ion - ions with 2+ charges are deflected more than ions with 1+

these combine into the mass/charge ratio (m/z)

Question 17

Detection

Answer 17

only +ions that have not been deflected will be detected.
other ions will be removed by the vacuum pump.

Question 18

Summary of mass spectrometry

Answer 18

V-sample vaporised
I- +ions are obtained from vapour
A- _ions are accelerated by an electric field
D- Deflected using a magnetic field
D- ions detected and recorded

Question 19

A mass spectrum tells you

Answer 19

> The atomic mass of all the isotopes
The relative abundances of each of the isotopes

Question 20

How to read a mass spectrum

Answer 20

> sizes/height of the peaks gives a measure of the relative abundances of the isotopes
Number of peaks shows the number of isotopes and their relative atomic masses

Question 21

Calculating Ar using the mass spectrum

Answer 21

Ar= (mass x abundance) + (massxabundance) / total of abundances