Maths Equations AS

Question 1

Relative isotope Ar

Answer 1

[(mass of A x isotope A %) + (mass of B x isotope B %)] ÷ sum of all %

Question 2

Moles

Answer 2

Mass ÷ Mr

Question 3

Moles

Answer 3

Concentration x volume (in dm)

Question 4

Moles

Answer 4

Number of particles ÷ Avogadro’s constant

Question 5

Volume of gas (dm)

Answer 5

Moles x 24

Question 6

Concentration in gdm

Answer 6

Concentration in mol dm x Mr

Question 7

Pressure

Answer 7

nRT ÷ V (PV = nRT)

P = Pa, V = m, T = K

Question 8

Molecular Formula

Answer 8

Empirical Formula x ‘multiplier’

Question 9

Percentage yield

Answer 9

(Actual yield / Theoretical yield) x 100

Question 10

Atom Economy

Answer 10

(Mr of desired product / Mr of all reactants) x 100

Question 11

Density

Answer 11

Mass / Volume

Question 12

Bond Enthalpy

Answer 12

∆H = bonds broken - bonds formed

(reactants - products)

Question 13

Enthalpy of Formation

Answer 13

Reactants - Products

Question 14

Enthalpy of Combustion

Answer 14

Products - Reactants

Question 15

Q

Answer 15

Q = MC∆T

Question 16

Enthalpy change

Answer 16

Q / number of moles reacting

Question 17

∆H per mole

Answer 17

Energy (kJ) / mol

Question 18

Kc

Answer 18

[C]c[D]d / [A]a[B]b

aA + bB ⇋ cC + dD