Year 1 - A level Flashcards
What are the 5 stages of mass spectroscopy
1-Vapourise sample 2-Ionisation(remove an electron) 3-Acceleration(using electric field) 4-Deflection(using magnetic field) 5-Detection
Ionisation energy
The energy required to remove 1 mole of electrons from 1 mole of gaseous atoms
What is an orbital?
Area of space which can hold a maximum of 2 electrons
How many electrons can be held in s, p and d subshells?
S - 1 orbital - 2e
P - 3 orbitals - 6e
D - 5 orbitals - 10e
What is the order of the first 5 shells?
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d
What is relative atomic mass?
The abundance of an elements isotopes using percentage to calculate an average atomic mass against a carbon 12 atom
What is an isotope?
Atoms with the same number of protons and different number of neutrons.
What effects ionisation energy?
- Electron shielding, further subshell lower I.E.
- No. protons, more protons higher I.E.
- Electron repulsion
How does I.E. change generally: -down a group, -across a period
Down group: 1st I.E. decreases as more shielding
Across period: Increases as more protons.
-Mg –> Al decrease since Al e coming from a higher subshell
-P –> S decrease as S electron is paired = more repulsion
Oxidation number for: Element, fluorine, hydrogen and oxygen(not with F or H)
element = 0 Fluorine = -1 Hydrogen = +1 Oxygen = -2
Steps to making 1/2 ionic equations?
- Balance all but H and O
- Add H2O to balance O
- Add H+ to balance H
- Add e- to balance charge
- Check with oxidation states
What is the reaction between Cl2 and a cold and hot alkali(e.g. NaOH)?
COLD: Cl2 + 2NaOH --> NaCl + H2O + NaOCl -Cl2 is reduced and oxidised called: Disproportionation reaction HOT: 3Cl2 + 6NaOH --> 5NaCl + NaClO3 + 3H2O
What is ΔH⦵?
Change in enthalpy
What is enthalpy?
Energy per mole
What does ⦵ mean?
Standard conditions, 100kPa and 298K
What does it mean when ΔH⦵ is negative or positive?
Negative = exothermic, surroundings gain heat Positive = endothermic, surroundings get colder
What is Q = mcΔT
Energy of surroundings = mass of surroundings x specific heat capacity x temp. change.
(In Joules)
What does energy change of system =?
Energy change of system = - energy change of surroundings
ΔH =?
ΔH = energy change of system / moles
Definition of bond energy?
Amount of energy required to break ‘1 mole of a particular bond’ for gaseous atom
Why aren’t bond energies correct?
They are averages
Define ΔH⦵c? Enthalpy of combustion
Enthalpy change when 1 mole of a substance is burnt in excess O2 under standard conditions
What are all the diatomic elements?
B,O,C,I,H,N,F(Becasue Of Chem I Have No Friends)
Define ΔH⦵f? Enthalpy of formation
Enthalpy change when 1 mole of a compound is formed from it’s elements, in their STANDARD STATES under standard conditions
ΔH⦵n? Enthalpy of neutralisation
Energy change when ‘1 MOLE OF WATER’ is formedin reduction between acid + base, under standard conditions
What are the 3 types of Hess Cycle?
- Given ΔH⦵c to work out ΔH⦵f
- Given ΔH⦵f to work out ΔH⦵ decomposition
- Work out ΔH⦵ solution
ΔH⦵ solution?
Difference between lattice energy and hydration energy
What is lattice energy?
Energy required to form 1 mole of ionic solid from gaseous ions, under standard states
What affects distortion(how good it is at polarising) in +ve ion?
-Small radius and high charge means best at polarising.
More distortion means furthest from ionic model and bigger gap between experimental and theoretical lattic enthalpies
What affects how the -ve ion is distorted?
-Close to 0 charge + big radius means easy to distort.
What is Entropy(S)
The number of ways of organising particles in a substance. Measured in JK-1mol-1?
- Many ways(gas) = high entropy
- Few ways(solid) = low entropy
ΔS =
ΔS = S products - S reactants
ΔG =
ΔG = ΔH - TΔS sys - change Δs by /1000
If -ve then spontaneous
Measured in KjMol-1
ΔS total =
Therefore ΔSsurr =
ΔS total = ΔS sys - ΔH/T - change ΔH x1000 for KJ to J
If +ve then spontaneous
Measured in JK-1Mol-1
ΔSsurr = -ΔH/T
What is the ideal gas equation?
pV = nRT
What are the three main gas laws?
- Boyle’s law
- Charles’ law
- Avagadro’s principle
What is Boyle’s law?
- Volume of a fixed mass of gas is inversely proportional to it’s pressure
- V ∝ 1/p
What is Charles’ law?
- The volume of a fixed mass of gas is directly proportional to its thermodynamic temperature
- V ∝ T
What is Avagadro’s principle?
- Equal volumes of different gases at the same temperature and pressure contain the same No. of molecules
- V ∝ n