4.2.4: Analytical techniques

Question 1

What effects does the absorption of infrared radiation have on covalent bonds ?

Answer 1

Vibrate more and absorb more energy

Question 2

Which greenhouse gasses in the atmosphere absorb infrared radiation and why ?

Answer 2

CO2, H20 AND CH3 as they contain C=O, C-O and C-H

Covalent bonds absorb the radiation and re-emit it back to Earth causing the greenhouse effect and global warming

Question 3

Give 2 uses of IR spectroscopy

Answer 3

• Emissions testing to monitor gases causing air polution
• Breathalysers to measure ethanol in breath by intensity of O-H peak

Question 4

Why is intensity of O-H peak not measured in brethalysers ?

Answer 4

Water is naturally found in breath which would create the O-H peak

Question 5

What does the highest peak at the end of mass spectrometry show ?

Answer 5

The molecular ion peak which has teh value of the Mr

Question 6

Give 2 pieces of evidence for global warming

Answer 6

• Air and water sample analysis
• Graphs show increase in temp and CO2 since 1970s