CH2 Amount of Substance Flashcards
Symbol for amount of substance
n
Unit used to measure amount of substance
mole
What does Avogadro constant represent
Number of atoms per mole of carbon-12 isotope
How to calculate mass of 1 mole of an element
mass of 1 mole = relative atomic mass in grams
How to calculate moles when mass and molar mass given
moles = mass/molar mass
Avogadro’s Law
Under the same temperature and pressure, 1 mole of any gas would occupy the same volume
How much volume does 1 mole of gas occupy at RT and pressure
24 dm3 or 24000 cm3
Define molar gas volume
The volume per mole of gas molecules
Why do different gas particles occupy the same volume
Gas particles are very spread out, hence individual differences have no effect
How to calculate moles when gas volume is given
moles = volume(dm3)/24 moles = volume(cm3)/24000
5 ideal ways in which gases behave
In continuous motion
No intermolecular forces experienced
Exert pressure when they collide with each other or container
No kinetic energy lost in collisions
When temperature increases, so does kinetic energy of gases
Ideal gas equation
pV = nRT
Pressure(Pa) x Volume(m3) = moles (mol) x Gas constant (8.314J mol-1) x Temperature (K)
1 atmospheric pressure = how many pascals
1 atm - 101325 Pa
0 degrees C = how many Kelvin
273 K
Waht does concentration of a solution mean
Amount of solute dissolved in 1 dm3 of solvent
How to calculate moles from concentration and volume
mole = Concentration x Volume
What is a standard solution
A solution of known concentration
Concentrated and dilute definitions
Concentrated - Large amount of solute per dm3 of solvent
Dilute - small amount of solute per dm3 of solvent
What is a species in a chemical reaction
Any particle that takes part in a reaction
4 common state symbols
Solid (s)
Liquid (l)
Gaseous (g)
Aqueous (aq)
What is percentage yield
The efficiency of which reactants are converted into products
Reasons why 100% yield is not obtained
Reaction may be at equilibrium
Impure reactants
Side reactions occurring
Reactants or products left behind when transferring
Loss of products during separation and purification
Calculating percentage yield
PY = (actual amount of product(mol)/theoretical amount of product(mol)) x 100
What does atom economy indicate
The proportion of desired products compared with all the products formed in the reaction
Calculating atom economy
AE = (molecular mass of desired product / sum of molecular masses of products) x 100
Which type of reaction has 100% atom economy
Addition reactions
