7. Equilibrium and Kp

Question 1

the mole fraction of a substance is

Answer 1

a measure of how much of a given substance is present in a reaction mixture

Question 2

the partial pressure of a substance is

Answer 2

the pressure an individual gaseous substance would exert if it occupied a whole reaction vessel on its own

Question 3

how to calculate mol fraction e.g. of substance A

Answer 3

mole fraction, X subscriptA= number of moles of substance A / total number of moles of all substances

Question 4

how to calculate partial pressure e.g of substance A

Answer 4

P superscriptA = mole fraction x total pessure

Question 5

units of pressure used within chemistry

Answer 5

atmospheres, atm
pascals, Pa (SI unit for pressure USE THIS)
newtons per square metre (Nm-2)

1atm=1.01 x 10 to the power of 5 Pa OR 101 kPa

1Pa =1Nm-2

Question 6

brackets used in Kp expressions

Answer 6

round brackets denote partial pressures

Question 7

Kp is used for

Answer 7

reactions involving gases

Question 8

calculating equilibrium constant Kp

Answer 8

aA+bB cC + dD

Kp= PRODUCTS /
REACTANTS

Kp= (PC)c (PD)d /
(PA)a (PB)b

Question 9

the expression for Kp when a reaction is hetrogeneous will change

Answer 9

solids not included in expression

pure liquids not included in expression

Question 10

if Kp is greater than 1

Answer 10

more products than reactants at equilibrium

Question 11

if Kp is less than 1

Answer 11

more reactants than products at equilibrium

Question 12

Kp is constant as long as there is a

Answer 12

constant temperature