chapter 3

Question 1

avogadro constant definition

Answer 1

the number of carbon-12 atoms that are in exactly 12g of carbon-12. it is 6.02x10^23 particles (given on data sheet)

Question 2

molar mass

Answer 2

the mass of one mole of substance, units=gmol^-1

Question 3

relative molecular mass

Answer 3

the mass of a molecule relative to 1/12th of the mass of an atom of carbon-12 (applies to molecular substances)

Question 4

relative formula mass

Answer 4

the mass of a formula unit relative to 1/12th of the mass of an atom of carbon-12 (applies to giant structures)

Question 5

anhydrous definition

Answer 5

containing no water molecules

Question 6

hydrated definition

Answer 6

a crystalline (solid) compound containing water molecules

Question 7

water of crystallisation

Answer 7

water molecules that are bonded into a crystalline structure of a compound

Question 8

at the same temperature and pressure, equal volumes of different gases contain…

Answer 8

the same number of molecules

Question 9

molar gas volume

Answer 9

1 mole (6.02x10^23 molecules) of any gas occupies the same volume at the same temperature and pressure

Question 10

molar gas volume at room temp and pressure

Answer 10

24.0dm^3mol^-1

Question 11

molar gas volume equation at RTP

Answer 11

V in dm3 = 24n
V in cm3 = 24000n

Question 12

a gas is said to be ideal if…

Answer 12

• the particles are in random motion
• collisions between particles are elastic
• particles have negligible size
• there are no intermolecular forces

Question 13

ideal gas equation (use when gases are not at RTP)

Answer 13

pV=nRT

Question 14

units of ideal gas equation

Answer 14

p = Pa
V = m3
n = moles
R = 8.314 (given)
T = K (degress+273)