Friday Quizzes

Question 1

By reference to the relevant part of the mass spectrometer, explain how the abundance of an isotope in a sample of rubidium is determined.

Answer 1

Detector

Current / digital pulses / electrical signal related to abundance

Question 2

State and explain the difference, if any, between the chemical properties of the isotopes 182W and 186W

Answer 2

None
Same electron configuration
(2)

Question 3

(a) Describe how the molecules are ionised using electrospray ionisation.

Answer 3

Sample is dissolved in a volatile solvent
1
Injected through needle/nozzle/capillary at high voltage/positively charged
1
Each molecule/particle gains a proton/H+

Question 4

State, in terms of the numbers of fundamental particles, one similarity and one difference between atoms of 50Cr and 53Cr

Answer 4

Same number of protons OR electrons
Different number of neutrons

Question 5

Give a reagent, that can be added to the solutions in each pair to distinguish between them in a single reaction.
State what is observed in each case. NaCl(aq) and BaCl2(aq)
[3 marks]
Reagent
Observation with NaCl
Observation with BaCl2

Answer 5

Reagent: H2SO4
Observation with NaCl: no (visible) change
Observation with BaCl2: white ppt / white solid formed forms BaSO4

Question 6

Explain how carbon monoxide is produced when petrol is burned in car engines.

Answer 6

incomplete combustion

(because) insufficient / limited
oxygen supply

Question 7

Give two effects of atmospheric pollution which are reduced by using
catalytic converters.

Answer 7

acid rain

• respiratory problems
• carbon monoxide
• global dimming or smog
  not global warming

Question 8

Describe how oxides of nitrogen are produced when petrol is burned in car engines.

Answer 8

nitrogen (from atmosphere)
reacts with oxygen (from
atmosphere)

at high temperature (in engine)
or
with a spark (from spark plug)