Amount of substance

Question 1

Standard conditions

Answer 1

• 25 degrees celsius or 298k
• 100kp or 1atm
• 1moldm^3

Question 2

Number of moles for solid

Answer 2

n =m/mr

Question 3

number of moles for a gas

Answer 3

n = V/24dm^3 or 24000cm^3

Question 4

number of moles for liquids

Answer 4

n = c x v

Question 5

ideal gas equation

Answer 5

pV = nRT

Question 6

Units for pressure, volume, temperature, ideal gas constant

Answer 6

pressure - Pa
volume - m^3
temperature- k
ideal gas constant - 8.314

Question 7

Convert cm^3 to m^3

Answer 7

multiply by 10 to the power of minus 6

Question 8

Convert dm^3 to m^3

Answer 8

multiply by 10 to the power of minus 3

Question 9

Convert degrees to kelvin

Answer 9

+273

Question 10

convert Kpa to Pa

Answer 10

multiply by 10 to the power of 3

Question 11

Amount of substance

Answer 11

Used to count the number of particles in a substance.

Question 12

Definition of mole

Answer 12

The amount of a substance that contains 6.02 x 10^23 particles.

Question 13

Avogadro constant

Answer 13

The number of particles in each mole of carbon -12.

Question 14

Empirical formula

Answer 14

The simplest whole number ratio of atoms of each element in a compound.

Question 15

Molecular formula

Answer 15

The number of atoms of each element in a molecule.

Question 16

Hydrated

Answer 16

A crystalline compound that contains water molecules.

Question 17

Anhydrous

Answer 17

A crystalline compound containing no water molecules.

Question 18

Water of crystallisation

Answer 18

Water molecules that form part of the crystalline structure of a compound .

Question 19

Molar mass

Answer 19

Mass in g in each mole of substance

Question 20

Standard solution

Answer 20

Solution of a known concentration.

Question 21

Stoichiometry

Answer 21

A ratio of amount/moles of each substance in balanced equation.

Question 22

Theoretical yield

Answer 22

Maximum possible product if all reactants have reacted and converted to product.

Question 23

Why may you not achieve theoretical yield?

Answer 23

• Reaction may not go to completion
• Side reactions may take place
• Purifications may lead to loss of product

Question 24

Formula for percentage yield

Answer 24

Actual yield/ theoretical yield x 100

Question 25

Limiting reagent

Answer 25

Reactant not in excess which will be used up first and stop reaction.

Question 26

Atom economy

Answer 26

A measure of how well atoms have been utilised.

Question 27

Formula for atom economy

Answer 27

Sum of mrs of desired products/ sum of mrs of all products

Question 28

What happens if you have high atom economy?

Answer 28

• Large proportion of desired products.
• Few waste products
• Important for sustainability- make most of resources
• Makes industrial processes more efficient, preserves raw material + reduces waste.

Question 29

How do you work out particles?

Answer 29

Number of particles = n x NA