Amounts of substance - 2 Flashcards
What is the symbol for amount of substance
n
What is the unit used to measure amount of substance
Mole
What does Avogadro constant represent
the number of atoms per mole of carbon 12 isotope
Equation for calculating moles
Moles = mass / mr
State Avogadro’s law
Under the same temperature and pressure, one mole of any gas would occupy the same volume
How much volume does a gas occupy at rtp
24 dm3
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, so individual differences has no effect.
How to calculate moles when gas volume is given
Moles = volume / 24
What are the ideal ways in which gases behave
They are in continuous motion
No intermolecular forces experienced
Exert pressure when they collide
No kinetic energy is lost in collisions
What is the ideal gas equation
Pv = nRT
1 atmospheric pressure is equal to how many pascals
1 atm = 101325 PA
0 degree Celsius is how many kelvin
273 K
What does concentration of solution mean
Amount of solute dissolved in 1 dm3 of solvent
Equation including moles, concentration and volume
Moles = conc * volume
What is a standard solution
A solution of known concentration
How do you prepare a standard solution
Weigh the solute using the weigh by difference method
In a beaker dissolve the solute using solvent
Pour the solution into a volumetric flask
Rinse the beaker using the solution and add it to the flask
Add solvent to flask carefully until it reaches the graduation line
Mix the solution thoroughly to ensure complete mixing
What does concentrated mean
Large amount of solute per dm3 of solvent
Define dilute
small amount of solute per dm3 of solvent
What is species in a chemical reaction
Any particle that takes part in a reaction
Define percentage yield
The efficiency of which reactants are converted into products
What are reasons for not obtaining 100% yield
Side reactions may occur
Incomplete reactions
Reactants or products may be left behind
Reactants may be impure
Formula for percentage yield
Percentage yield = actual amount / theoretical amount
What does atom economy tell us
The proportion of desired products compared with all the products formed in the reaction
