Topic 3 - Amount of substance

Question 1

Relative isotopic mass

Answer 1

The mass of an atom of an isotope compared to 1/12th mass of a carbon-12 atom

Question 2

Relative atomic mass

Answer 2

The weighted mean mass of an atom of an element compared to 1/12th of a mass of a carbon-12 atom

Question 3

Relative molecular mass

Answer 3

The average mass of a molecule compared to 1/12th of the mass of a carbon-12 atom

Question 4

Relative formula mass

Answer 4

The average mass of a formula unit compared to 1/12th mass of a carbon-12 atom

Question 5

Calculating RAM

Answer 5

• Isotope’s RIM x abundance
• sum it together
• divide by sum of isotopic
  abundances

Question 6

Avogadro’s constant

Answer 6

6.02 x 10^23

Question 7

What does ionic compounds consist of?

Answer 7

A lattice of alternating + and - ions

Question 8

What is an ionic compound without water of crystallisation called?

Answer 8

Anhydrous

Question 9

What is an ionic compound with wawter of crystallisation called?

Answer 9

Hydrated

Question 10

What are the 2 ways of measuring the concentration of a solution

Answer 10

• g dm-3
• mol dm-3

Question 11

Equation of conc for g dm-3

Answer 11

mass/
volumes

Question 12

Equation of conc for mol dm-3

Answer 12

mol /
volume

Question 13

convert cm3 to dm3

Answer 13

divide by 1000

Question 14

converting g dm-3 to mol dm-3

Answer 14

g dm-3 divided by Mr

Question 15

convert mol dm-3 to g dm-3

Answer 15

mol dm-3 x Mr

Question 16

What is the molar gas volume?

Answer 16

The volume occupied by one mole of any gas at constant temperature and pressure

Question 17

What is the molar gas volume measured in

Answer 17

dm^3 mol^-1

Question 18

What are the standard room temperature conditions for molar gas volume

Answer 18

293K (20C)

Question 19

What are the standard pressure conditions for molar gas volume

Answer 19

101kPa

Question 20

Equation for moles at standard room conditions

Answer 20

Vm = n / V

Question 21

What is the value of gas molar volume at standard conditions

Answer 21

24 dm^3

Question 22

How can you measure the volume of gas produce in a reaction (standard conditions)

Answer 22

• gas syringe
• water displacement

Question 23

Kinetic theory of gases assumptions

Answer 23

• gas particles move rapidly and
  randomly
• No inter molecular attractions or
  repulsion
• collisions between particles are
  elastic - no energy is lost
• Average kinetic energy of particles
  depends only on their
  temperature

Question 24

The ideal gas equation

Answer 24

pV = nRT

p - pressure
V - volume
n - moles
R - gas constant (8.31Jk^-1 mole^-1)
T - temperature

Question 25

What is pressure measured in? (ideal gas)

Answer 25

Pa

Question 26

What is volume measured in (ideal gas)

Answer 26

m^3

Question 27

what is temperature measured in (ideal gas)

Answer 27

K

Question 28

empirical formula

Answer 28

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