Chemical Reactions & Equilibrium Flashcards

1
Q

Describe the criteria for a successful collision

A

-reactant molecules must collide with each other
-reactant molecule must collide with sufficient energy to break the bonds within the reactants
-reactant molecules must collide with the correct orientation to break the bonds within the reactants

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2
Q

define rate of reaction

A

the change in concentration of the reactants or products per unit time

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3
Q

How does increased surface area influence rate of reaction

A

increase surfaced area
increased frequency of successful collisions per unit time
increased rate of reaction

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4
Q

How does increased concentration influence rate of reaction

A

increase concentration
increase number of particles in a given volume
increase frequency of successful collisions per unit time
increased rate of reaction

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5
Q

how do you increase pressure

A

decrease the volume of the system

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6
Q

how do you decrease pressure

A

increase the volume of the system

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7
Q

How does increased pressure inference rate of reaction

A

increase pressure
increase concentration of particles
increase frequency of successful collisions per unit time
increased rate of reaction

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8
Q

How does increased temperature influence rate of reaction

A

increase temperature
increased average kinetic energy
increased proportion of particles with energy greater than or equal to the activation energy
increased frequency of successful collisions per unit time
increased rate of reaction

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9
Q

Two types of catalysts

A

homogenous and heterogenous

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10
Q

How do catalysts increase rate of ration

A

provide an alternative reaction pathway by lowering activation energy and in turn increasing the proportion of particles with energy equal to or above the activation energy.

increasing the frequency of successful collisions per unit time and increasing rate of reaction

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11
Q

define equilibrium

A

when the forward and back reactions occur at the same rate, the reaction is said to be at equilibrium

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12
Q

Identify conditions at equilibrium

A

-amount of mol of substance is constant
-concentration of substances is constant
-pressure constant (gas system)
-temperature constant

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13
Q

purpose of Kc value

A

it shows the extent of the reaction

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14
Q

how to calculate Kc value

A

concentration of product(s) to power of coefficient / concentration of reactant(s) to power of coefficients

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15
Q

what impacts Kc

A

temperature ONLY

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16
Q

How to get units of Kc

A

coefficients of product / coefficients of reactant (simplify)

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17
Q

If Kc is greater than 10^4 then

A

reaction goes to completion (negligible amount of reactant left)

18
Q

If Kc is less than 10^-4 then

A

reaction occurs to a negligible extent (negligible amount of product formed)

19
Q

Kc values between 10^-4 and 10^4 are

A

indicative of the forward and back reactions occurring to a moderate extent

20
Q

Find K2 for the reverse reaction of K

A

1/K

21
Q

Find K2 for the coefficients of reaction K being doubled

A

K^2

22
Q

Find K2 for the coefficients of reaction K being halved

A

K^1/2

23
Q

How is Kc influenced in EXOTHERMIC reaction

A

increase in temperature decreases K
decrease in temperature increases K

24
Q

How is Kc influenced in ENDOTHERMIC reaction

A

increase in temperature increase K
decrease in temperature decreases K

25
Q

What is Q (reaction coefficient)

A

same calculation as K but not necessarily at equilibrium

26
Q

How are Q and Kc related to equilibrium

A

if Kc<q>Q then the system will shift right to achieve equilibrium and more products will form
if Kc = Q then the system is at equilibrium</q>

27
Q

ICEFC stands for

A

initial mol
change in mol
number of mol at equilibrium
Final CONCENTRATION

28
Q

Key principal of Le Chatelier’s

A

if an equilibrium system is subjected to change then the system will shift in a direction that PARTIALLY OPPOSES that change

29
Q

How does temperature influence equilibrium yield

A

An increase in temperature will be partially opposed by favouring the energy absorbing endothermic reaction

A decrease in temperature will be partially opposed by favouring the energy releasing exothermic reaction

30
Q

How do catalysts influence equilibrium yield

A

NO change as they effect the rate of the forwards and reverse reactions to an equal extent

31
Q

How does the addition of an inert gas influence equilibrium yield

A

has no effect on the position of equilibrium, provided the volume of the container remains constant

32
Q

Name 3 inert gases

A

He
Ne
Ar

33
Q

How does the addition of a reactant or product influence equilibrium

A

addition of a product or reactant increases the concentration of that reactant or product and hence the reaction that uses up that reactant or product will be promoted to partially opposes the increase in concentration of the reactant or product and hence decrease the concentration of that reactant or product

34
Q

How does removal of a reactant or product influence equilibrium

A

removal of a product or reactant decreases the concentration of that reactant or product and hence the reaction that produces that reactant or product will be promoted to partially opposes the decreases in concentration of the reactant or product and hence increase the concentration of that reactant or product

35
Q

How does dilution impact equilibrium

A

a dilution decreases the concentration of all the reactants and products and is partially opposed by favouring the reaction that produces more mol of solution

36
Q

How does volume influence pressure

A

increase volume decreases pressure & decrease volume increases pressure

37
Q

How does pressure impact equilibrium

A

increase in pressure is partially opposed by promoting the reaction that produces fewer mole of gas
decrease in pressure is aerially opposed by favouring the reaction that produces more mole of gas

38
Q

Write the two chemical reactions for CO poisoning

A

Hb4 + 4O2 –> Hb4O8. -K1
Hb4 + 4CO –> Hb4(CO)4. -K2

39
Q

Why is CO poisoning dangerous

A

Because K2 is much greater than K1 then even at very low concentrations haemoglobin in the blood and CO bind to form the complex - Hb4(CO)4

40
Q

Why would high concentrations of oxygen be delivered for CO poisoning

A

By pumping in oxygen, this increases the oxygen concentration and favours the forward reaction to produce Hb4O8. This reduces the amount of Hb4 in the blood and as a result the second reaction will shift left to partially opposes the decrease in Hb4 concentration and produce more Hb4. Less Hb(CO)4 complexes form and CO poisoning is minimised

41
Q

why does addition of inert gas have have no effect on ror

A

inert gas particles are not apart of the reaction and hence do not affect the number of collisions and successful collisions per unit time.