Amount of Substance Flashcards
Define amount of substance.
Quantity whose unit is the mole.
Define mole.
Amount of substance containing 6.02 x 10^23 particles.
Equation for moles (no. of particles)?
mol = P/Avo constant
P = mol x Avo
Avogadro’s constant?
6.02 x 10^23. Number of particles in 1 mole of any substance.
Equation for moles (mass and Mr)?
mol = mass/Mr
mass = mol x Mr
Mr = mass/mol
Define molar mass.
The mass of 1 mole of any substance (in g mol^-1).
Equation for density?
density = mass/volume
mass = density x vol
vol = mass/density
Why can measuring the mass of a gas be difficult?
The gas may be more dense than air so it floats.
Define molar gas volume.
The volume of 1 mole of any gas at RTP (room temp and pressure).
What is RTP (room temp and pressure)?
Temp = 298 K
Pressure = 100 kPa/1
What is the volume of 1 mole of any gas at RTP?
24.0 dm^3 mol^-1
Volume is what to number of moles?
Proportional.
Equation for volume of a gas at RTP?
vol = mol x 24.0
mol = vol/24.0
Ideal Gas Equation?
PV=nRT
- P = nRT/V
- V = nRT/P
- n = PV/RT
- T = PV/nR
n = moles
R = gas constant (8.31, provided)
When is the ideal gas equation used?
In gases NOT at RTP.
State conversions for units in the ideal gas equation.
kPa to Pa = x1000
dm^3 to m^3 = /1000
cm^3 to m^3 = /1,000,000
oC to K = +273
