Chapter 4 - Ozone Story

Question 1

how can you find the concentration of iodine in a solution

Answer 1

titrate it with sodium thiosulfate

• add starch to the iodine in the beaker making it a deep blue colour
• titrate with sodium thiosulfate
• end point is when deep blue turns colourless

Question 2

what is a radical

Answer 2

an atom or molecule with an unpaired electron

Question 3

what is homolytic fission

Answer 3

when one electron goes to each atom forming radicals

Question 4

what is heterolytic fission

Answer 4

when both electrons go to one atom forming ions

Question 5

how can you convert % into ppm

Answer 5

convert % into decimals 
then x1000000 (million)

Question 6

how can you work out the energy to break one bond

Answer 6

energy required for 1 mole of bonds/ 6.02x10^23

Question 7

what is plancks constant

Answer 7

6.63x10^-34

Question 8

in the stratosphere what does ozone do

Answer 8

absorbs ultraviolent radiation protecting earth

Question 9

in the troposphere what does ozone do

Answer 9

at ground level ozone is a significant pollutant

Question 10

what do CFCs do

Answer 10

removes ozone in the stratosphere by reacting with O3

not good

Question 11

what is activation enthalpy

Answer 11

the minimum energy in a collision required for a successful reaction

Question 12

what is a homogeneous catalyst

Answer 12

catalysts that are in the same state as reactants

Question 13

what is electronegativity

Answer 13

the ability of an atom to attract electrons in a covalent bond

Question 14

what is a nucleophile

Answer 14

an ion or molecule that has a lone pair of electrons that it can donate to a positively charged centre to form a covalent bond

Question 15

to form a hydrogen bond you need…(HONF ALPONF)

Answer 15

• a hydrogen with a partial positive charge on an electronegative atom (O,N,F)
• a lone pair on an electronegative atom (O,N,F) with a partial negative charge