Chapter 19

Question 1

What is an ice table

Answer 1

An ice table is used to calculate equilibrium quantities it stands for initial change and equilibrium

Question 2

For the following question use an ice table calculate equilibrium concentrations and find the value of kc

in a reaction 1.6 moles of NO and 1.4 moles of O2 are mixed in a container volume 4 decimeters cubed at equilibrium 1.2 moles of no2 is formed

2NO + O2 = 2NO2

Answer 2

KC = 45dm3mol-1

Question 3

What is a homogeneous equilibrium

Answer 3

Homogeneous equilibrium is where all equilibrium species have the same state / phase

Question 4

What is a heterogeneous equilibrium and what does this mean for KC

Answer 4

A heterogeneous equilibrium is where equilibrium species have different states / phases

Any solids and liquids are left out of KC

Question 5

What is a mole fraction

Answer 5

A mole fraction is the proportion of gas in a gas mixture

Mole fraction x(A)= moles of A/total number of moles

Question 6

What is partial pressure

Answer 6

Partial pressure is the pressure exerted by a gas and when added to all other partial pressures to make total pressure

Partial pressure= mole fraction x total pressure

Question 7

an equilibrium mixture at 400 degrees contains 18 mole of N2 54 mole of H2 and 48 ml of nh3 total pressure is 200 atmospheres find KP

N2+ 3H2 → 2NH3

Answer 7

KP is equal to 2.9 x 10 ^-4 atm-2

Question 8

What does a k value of 1 mean

Answer 8

If k is equal to 1 equilibrium is halfway between reactants and products

Question 9

What does a k value of 100 mean

Answer 9

If K is equal to 100 equilibrium lies further to the right favouring the products

Question 10

What does a k value of 0.01 mean

Answer 10

Is k is equal to 0.0 one equilibrium lies to the left favouring the reactants

Question 11

How does temperature affect the position of equilibrium and the value of KC/KP

Answer 11

According to le chatelier’s principle if temperature is increased and the forward reaction is exothermic equilibrium will shift to the left in the endothermic direction

This will decrease the value of K as it favours reactants over products so the number on the bottom of the expression will be larger

Question 12

How does pressure and concentration affect the position of equilibrium and the value of KC / KP

Answer 12

according to the chatelier’s principle if concentration is increased equilibrium will shift in the direction that reduces it and if pressure is increased equilibrium will shift to the side with fewer gaseous moles

K is unaffected by changes in concentration and pressure