wrong questions

Question 1

describe one difference between the pi and sigma bond

Answer 1

sigma bond is between bonding atoms
pi bond is above and below the bonding atoms

Question 2

explain why a compound does not have e/z isomers

Answer 2

one carbon atom in the double bond is attached to 2 groups which are identical

Question 3

write two equations to show how NO radicals catalyse the breakdown of ozone in the stratosphere

Answer 3

NO* + O3 = NO2* + O2
NO2* + O = NO* + O2

Question 4

explain in terms of bond breaking and bond making why the enthalpy change of formation of NO is endothermic

Answer 4

more energy is requires for bond breaking than is released by bond making

Question 5

dilution equation

Answer 5

new diluted concentration = original conc x original volume/new diluted volume

Question 6

if kp decreases as temperature increases is the forward reaction exothermic or endothermic (same for the value of Kc)

Answer 6

exothermic

Question 7

how does increasing the pressure change equilibrium position in terms of kp

Answer 7

eq shifts to side with fewer moles eg to the RHS
- ratio in Kp expression decreases
- ratio increases to restore kp
- kp does not change as it only changes with temp

Question 8

percentage dissociation equation

Answer 8

[H+]/acid x 100

Question 9

explain why it is difficult to predict whether the enthalpy change of solution becomes more exothermic or less exothermic down the group from MgF2 to MgI2

Answer 9

• halide ion gets larger down the group
• lattice enthalpy is less exothermic down the group
• hydration enthalpy is less exothermic down the group
• difficult to predict whether lattice enthalpy of hydration enthalpy has bigger effect

Question 10

explain why 1-iodopentane was found to react faster than 1-bromopentane

Answer 10

c-i bond is weaker
carbon halogen bond breaks

Question 11

in enthalpy of combustion experiments would the experiment be improved by heating the water for longer

Answer 11

less accurate due to greater heat losses
more accurate due to smaller percentage uncertainty in temperature change

Question 12

explanation for major product

Answer 12

the carbocation intermediate is more stable

Question 13

in an arrhenius plot what is the x and what is the y axis

Answer 13

x = 1/T
y= ln(rate) or ln(1/time)

Question 14

graph shapes for a rate/concentration graph

Answer 14

zero order is a straight horizontal line as it has NO effect on the rate

Question 15

exothermic explanation

Answer 15

Bond breaking requires less energy than is released by bond formation.

Question 16

IR

Answer 16

causes covalent bonds to vibrate more and absorb energy