2.1.3 Flashcards
What is the numerical value of a mole
6.02x10^23
Relationship using avrogados constant
Number of moles (n) = number of particles / avrogados number
Definition of a mole of a substance
The amount of that substance that contains as many elementary particles as there are carbon atoms in 12 grams of carbon 12
Difference between relative formula mass and molar mass
Molar mass has units relative formula mass doesn’t
Moles =
Mass / molar mass
Method for determining the water of crystallisation in hydrated crystals
1) weigh empty crucible
2) add hydrated salt then weigh again
3) heat until constant mass
4) record final mass after cooling
What is the relationship between moles and volume
N= volume/ molar volume (24000cm3)
Volume and molar volume have to be in the same unit
What is the ideal gas equation
pV=nRT
p= pressure in PA
V= volume in m3
n= moles
R= gas constant
T= temperature in K
1 KPa =
1000Pa
How do you get from cm3 to m3
Divide by 1000000
How do you get from dm3 to m3
Divide by 1000
How do you get from Celsius to kelvin
Add 273
What does the ideal gas model assume
- particles are in constant motion
- there are no IMF between molecules or atoms
- gas particles occupy 0 volume
- collisions between particles are elastic
Percentage yield =
Amount of product actually produced / theoretical amount of product
G to tonnes = x 1000000
Reasons why percentage yield will never be 100 percent
- reaction could be reversible
- other product produced
- transfer loss- left in vessel when moved
- impure reactant
- purifaction losses- hard to separate from other products
