Section 5- The Ozone Story Flashcards
(7 cards)
What is the definition of electronegativity?
The ability of an atom to attract the bonding electrons in a covalent bond
Although differences in electronegativity may induce a polar bond, sometimes it doesn’t, why is this?
There is a balance in charges, and there is no overall dipole. A common example is CO2.
Explain how instantanous dipole induced dipoles form.
What is the trend of such forces?
Electrons in an atom are constantly moving, and may become more distributed on one side of an atom than another, which induces a temporary dipole, this will then cause the electrons in an adjacent atom to shift in position in reponse to this, making it also have a temporary dipole. This will mean the two atoms are temporarily attracted to eachother, and this has a knock on affect. However, as the electrons are constantly moving, they break forces and reform them constantly.
They increase in strength the heavier the atom becomes because there are more electrons in the atom.
What are the different ways you could measure the rate of a reaction?
Measure volume of gas produces
Measuring the changes of mass
Measuring any pH changes
Measuring and Temperature change
Measuring concentrations at regular intervals by quenching and then titrating.
Then plot a curve, of whatever youve measured against time, and then draw a tangent at the time you require.
As a Haloalkane has halogens attached which make more polar bonds, what does it make the molecule more likely to have occur to it?
Nucleophillic substitution. The partial charge of the halogen will attract nucleophiles more as the carbon will be more positively charged. Nuceophiles include water, OH, and NH3.
Reactivity of haloalkanes is decided by the bond enthalpy of the relevant haloalkane. Describe the trend.
The bond enthalpy is strongest nearest the top of the group and decreases as you go down. This is due to shorter atomic radius and less electron shielding. The closer to iodine the bond is the weaker the bond is, meaning its more likely to be broken and react. It is the case that enthalpy trumps polarity.
Why are chlorine radicals from CFC’s have such a negative impact on the breakdown of ozone?
They catalyse the break down of it. They are reformed at the end of the radical mechanism, and are able to go ont catalyse further ozone molecules. Many ozone molecules can be catalysed by single chlorine radicals.
