Topic 7: Equilibrium

Question 1

physical system

Answer 1

rate of codensation= rate of evaporation= rate of melting

Question 2

chemical system

Answer 2

rate of reaction of produts and reactants equal

Question 3

features of equillibrium

Answer 3

• its dynamic
• in a closed system
• product and react CONCENTRATIOn is constant
• no macroscophic changes
• equillibrium can be reached from either direction

Question 4

equillibrium position (Q)

Answer 4

proportion of reactants and products in equillibrium mixture
left (in favour of reactants)
right ( in favour of products)

Question 5

Kc

Answer 5

equillibrium constant; fixed value for a particular reaction at specified temperature for which the sytem is at equillbirum
- only temp affects Kc

Question 6

kc formula

Answer 6

products/reactants

Question 7

kc magnitude

Answer 7

shows the extent of the reaction
(small Kc; in favour of reactants;
large Kc; in favour of products)
when kc= 1; equillibrium

Question 8

reaction quotient

Answer 8

Q; meausure of relative amounts of reactnants and products present in a reaction at a particuarl time (substitute reaction concentration into Kc expression)

Question 9

la chateliers principle

Answer 9

a system as equillibrium when disrupted will response in such a way to minimized the effects of change

Question 10

change in conc

Answer 10

• increase in reactants; E shifted to right

- increase in products; E shifted to left

Question 11

change in pressure

Answer 11

only affects gaseous molecules with unequal ration of gas molecules on each side
-system favours side with few gas molecules with the increase of pressure

Question 12

changes in temp

Answer 12

• change kC value

exothermic reactions; increase in temp shifts E to left to favour reactants in forward reactions (heat as product)
- kc decreases

endothermic reactions: increase in temp shifts right to favour products in forward reaction (heat as a reactant)
- kc increases

Question 13

catalyst

Answer 13

speeds up rate at with equillibrium is reached

• increases rate equally of forward + backward reactions
• doesnt affect Kc or equillibrium positions

Question 14

haber process

Answer 14

production of ammonia: exothermic forward reaction
high pressure (4:2 ratio of gaseos molecules)
medium temperature of 450.c (exoterhmic reaction; need fast reaction rate but also high yield)

catalyst: iron, aluminum or magneisum oxides
ruthenium

Question 15

contact process

Answer 15

combustion of sulfur to form SO2
oxidation of sulfur to form SO3
SO3 + water to produce sulfuric acid

• high pressure
• moderate tempreature (450C)
• cataluyst; vanadium (V) oxide

Question 16

methanol production

Answer 16

production of methanol from carbon monoxide and hydrgen (exothermic)
- high pressure 
- low temperature (250C)
Catalyst:
- copper
-zinc oxide
-aluminium trioxide