topic 5 - formulae, equations and amounts of substance

Question 1

what is the mole

Answer 1

the amount of substance in grams that has the same number particles in 12 grams of carbon 12

Question 2

what is molar mass

Answer 2

the mass in grams of 1 mole of a substance and is given the unit of g mol-1

Question 3

what is the relative atomic mass

Answer 3

the average mass of one atom compared to one twelvth of the mass of one atom of carbon 12

Question 4

equation for pure solids, liquids and gasses

Answer 4

mass=mr moles

Question 5

calculation for gases

Answer 5

gas volume (dm3) = amount x 24

Question 6

calculation for solutions

Answer 6

concentration = amount / volume

Question 7

assumptions of ideal gas equation

Answer 7

• no IMF’s exist between molecules of a gas
• volume occupied by gas molecules is neglibile

Question 8

ideal gas equation

Answer 8

PV = nRT

Question 9

what is the empirical formula

Answer 9

an empirical formula is the simplest ratio of atoms each element in the compound

Question 10

ideal gas equation units

Answer 10

pressure = Pa or N/m2
volume = m3
temperature = K ( C + 273 )
gas constant (R) = 8.31 J K-1 mol-1