Module 3 Keywords Flashcards
Periodicity
The repeating trends in properties of the elements
First ionisation energy
The energy required to remove an electron from each atom in one gaseous mole of an element to make one gaseous mole of 1+ ions
Second ionisation energy
The energy required to remove an electron from each ion in one gaseous mole of 1+ ions an to make one gaseous mole of 2+ ions
Metallic bond
Electrostatic force of attraction between delocalised electrons and the positive metal cation
Covalent bond
Strong electrostatic force of attraction between a shared pair of electrons and the nuclei of the bonded atoms
Ionic bond
Electrostatic force of attraction between two oppositely charged ions
Reducing agent
A reagent that gives electrons to another species, reducing that species
Oxidising reagent
A reagent that takes electrons from another species, oxidising that species
Reduction
Gain
Oxidation
Loss
Disproportionate reaction
When the same element is both ox and red
The chemical system
Atoms molecules or ions making up the chemicals
System
Chemicals, the reactants and products
Surroundings
The apparatus the lab and everything tat isn’t the chemical system
Universe
Everything. Both the surrounding and the universe
Exothermic
When the energy released making new bonds is larger than the energy absorbed breaking the old bonds Negative delta h Chemical system loses energy Surroundings gains energy Temperature of surroundings increase
Endothermic
When the energy released making new bonds is smaller than the energy absorbed breaking the old bonds. Positive delta h Chemical system gains energy Surroundings loose energy Temperature of surroundings decrease
Activation energy
Minimum energy required to initiate a reaction by the breaking of bonds
Standard conditions
Standard pressure of 100Kpa
Standard temperature of 298K
Standard concentration (for solutions only) 1moldm3
Standard state
Standard state
Physical state of a substance under standard conditions of 100Kpa and 298K
Standard enthalpy change of reaction
The enthalpy change that accompanies a reaction in the molar quantities shown in the chemical equation under standard conditions with all products and reactants in their standard states
SECF
The enthalpy change that takes place when one mole of a compound is formed from its elements under standard conditions with all products and reactants in their standard states
SECC
The enthalpy change that takes place when one mole of a substance is reacts completely in excess oxygen under standard conditions with all products and reactants in their standard states
SECN
The enthalpy change that accompanies the reaction of an acid by a base to make one mole of water under standard conditions with all products and reactants in their standard states
Specific heat capacity
The temperature required to raise 1g of a substance by 1K
Average bond enthalpy
The energy required to break one mole of a specified type of bond in a gaseous molecule.
*value depends on chemical environment
Rate of reaction
The change in concentration of the product or reactants in a given time
Homogeneous catalyst
Is in the same physical state as the REACTANTS
Heterogeneous catalyst
Is in a different physical state as the REACTANTS
Adsorption
Substance is weakly bonded to the surface of the catalyst
Desorption
Product molecules leave the surface of the catalyst
Absorption
Substance is weakly bonded within the the catalyst
Dynamic equilibrium
Closed system
Concentrations are constant
Rates are equal
Catalyst
Provides an alternate pathway for the reaction to happen with a lower activation energy, increasing the proportion of molecules with sufficient energy to react.
