Chemistry Flashcards
How does particle size affect reaction rate?
Particle size decrease, larger total surface area to volume ratio, collision frequency increases, successful collision frequency increases, reaction rate increases.
Reaction Kinetics, pg. 12
How does concentration affect reaction rate?
Higher concentration, more reacting particles per unit volume, collision frequency increases, successful collision frequency increases, reaction rate increases.
Reaction Kinetics, pg. 16
How does pressure affect reaction rate?
Higher gas pressure, more reacting particles per unit volume, collision frequency increases, successful collision frequency increases, reaction rate increases.
Reaction Kinetics, pg. 17
How does temperature affect reaction rate?
Higher temperature, higher kinetic energy of reacting particles, greater proportion of reacting particles collide with energy greater than or equal to activation energy, successful collision frequency increases, reaction rate increases.
Reaction Kinetics, pg. 18
How do catalysts affect reaction rate?
Catalyst provides lower activation energy alternative pathway, greater proportion of reacting particles collide with energy greater than or equal to lowered activation energy, successful collision frequency increases, reaction rate increases.
Reaction Kinetics, pg. 20
How does reactant concentration affect equilbrium position?
When more reactant X is added, by Le Chatelier’s principle, forward reaction favoured to remove some excess reactant X. Equilibrium position shifts right.
Chemical Equilibrium, pg. 53
How does pressure affect equilibrium position?
When pressure increased, by Le Chatelier’s principle, for/backward reaction favoured to decrease number of moles of gaseous particles in order to decrease pressure, equilibrium posiiton shifts left/right.
Chemical Equilibrium, pg. 55
How does temperature affect equilibrium position?
When temperature increased, energy added, by Le Chatelier’s principle, endothermic reaction (ΔH>0) favoured to absorb some heat energy, the for/backward reaction favoured, equilibrium position shifts left/right.
When temperature decreased, energy removed, by Le Chatelier’s principle, exothermic reaction (ΔH<0) favoured to release some heat energy, the for/backward reaction favoured, equilibrium position shifts left/right.
Chemical Equilibrium, pg. 58
How do catalysts affect equilibrium position?
When catalyst added, activation energy of both forward and backward reactions lowered, both reaction rates increase by the same extent, new equilibrium reached in shorter time, no change to equilibrium position.
Chemical Equilibrium, pg. 60
Name the reactivity series
Please Stop Calling Mary A Clumsy Zebra It’s Lame How Can She Gallop
Potassium Sodium Calcium Magnesium Aluminum Carbon Zinc Iron Lead Hydrogen Copper Silver Gold
What happens to OH- in electrolysis?
4OH- (a1) : O2 (g) + 2H2O (l) + 4e-
1-4 C fraction?
Refinery gas
5-10 C fraction?
Petrol/naphtha
10-16 C fraction?
Kerosene
13-25 C fraction?
Gas oil
> 25 C fraction?
Residue
How does carbon chain length affect b.p./m.p.?
Carbon chain length increases, larger electron cloud more easily polarised, more energy needed to overcome stronger london forces, b.p./m.p. increases.
How does degree of branching affect m.p./b.p.?
Greater branching, smaller surface area in contact with other molecules, less energy needed to overcome weaker london forces, m.p./b.p. decreases.
Describe combustion/oxidation of alkanes/alkenes
Alkane/alkene + Oxygen : Carbon dioxide + Water
Describe halogenation of alkanes and conditions
Alkane (CH3) + Halogen (X2) : CH3X + HX
Presence of UV light
Describe cracking process and conditions
Long chain alkanes : short chain alkenes + short chain alkanes OR H2
Alumina catalyst, 500C, 1atm
Describe hydrogenation/reduction of alkenes
Alkene + H2 : Alkane
Platinum catalyst, 150C, high atm
Describe halogenation of alkenes, conditions and observations
Alkene + Cl2/Br2 : Haloalkane
Dark room, rtp
Cl2/Br2 decolourised
Describe hydration of alkenes and conditions
Alkene + Steam : Alcohol
Phosphoric acid catalyst, 300C, 60 atm
How does alcohol classification affect b.p./m.p?
Tertiary alcohols are surrounded by large alkyl groups, less energy needed to overcome less extensive hydrogen bonding network, m.p./b.p. decreases.
How does carbon chain length affect alcohol solubility?
Longer carbon chain hinders formation of hydrogen bonds between water molecules and alcohol molecules, so they are less soluble.
Yeast reaction?
C6H12O6 : 2C2H5OH + 2CO2
Describe oxidation of alcohols to carboxylic acids and conditions
Alcohol + 2[O] : Carboxylic acid + water
KMNO4/K2Cr2O7 catalyst, heat under reflux
Describe esterification/condensation reaction between alcohols and carboxylic acids and conditions
Alcohol + Carboxylic acid : Ester + water
H2SO4 catalyst, heat under reflux
Describe hydrolysis of esters and conditions
Ester + water : Alcohol + Carboxylic acid
Dilute HCl catalyst, heat under reflux
