Module 5 Keywords

Question 1

zero order

Answer 1

the concentration of the reactant has no effect on the rate

Question 2

first order

Answer 2

the rate of the reaction depends on the concentration of the reactant raised to the power one
*any change you make to the concentration of the reactant gives the same change to the rate

Question 3

second order

Answer 3

The rate of the reaction depends on the concentration of the reactant raised to the power 2

Question 4

initial rate

Answer 4

instantaneous rate at the beginning of an experiment when t=0

• the change in concentration per unit time at the start of the reaction

Question 5

half life

Answer 5

the time taken for the concentration of a reactant to decrease by half

Question 6

rate of reaction

Answer 6

the change in concentration of a reactant or product per unit time

Question 7

order of reaction

Answer 7

the magnitude that a reactant affects the reaction

Question 8

overall order

Answer 8

The sum of the individual orders

Question 9

reaction mechanism

Answer 9

A series of steps that make up the overall reaction

Question 10

rate-determining step

Answer 10

the slowest step in a multi-step reaction sequence. provides evidence for rejecting or accepting a proposed reaction mechanism

*this makes up the rate equation. but orders and species must match. catalysts aren’t allowed but intermediates are, just have to show how they’re made

Question 11

stoichiometry

Answer 11

gives you the relative amounts of the species in the reaction (must b balanced)

Question 12

Heterogeneous equilibrium

Answer 12

Contains equilibrium species with different states of phases

Question 13

Homogeneous equilibrium

Answer 13

Contains equilibrium species that all have the same state or phase

Question 14

Mole fraction

Answer 14

Moles divided by total moles in gas mixture

• Same as the gas’s proportion by volume to the total volume of gas in a gas mixture
• sum must equal 0

Question 15

Partial pressure

Answer 15

The contribution that a gas makes towards the total pressure

Mole fraction times total pressure.

*Sum of partial pressure is total pressure.

Question 16

Voltaic cells

Answer 16

Covert chemical energy into electrical energy. For this you need chemical reactions that transfer electrons from one species to another. Redox reactions!

Connect two half cells to make the cell.

Question 17

Standard electrode potential

Answer 17

The emf of a half cell compared to the standard hydrogen half cell under standard conditions of 100KPa 1moldm3 and 298K

Question 18

Primary cells

Answer 18

Non rechargable

Designed to be used once only.

Question 19

Secondary cell

Answer 19

Rechargeable
Eg.
-Lead acid batteries in car batteries
-Nickel cadmium NiCd
Cells and Nickel metal hydrides NiMH the cylindrical batteries used in radios and torches etc
-lithium ion and lithium ion polymer cells used in modern appliances. Laptops tablets cameras mobiles etc. Also being developed for cars

Question 20

Fuel cells

Answer 20

Use the reaction of a fuel with O2 to make a voltage. Constant supply of O2 and fuel enables the cell to operate continuously.
Nah have to be recharged

Question 21

Electrolyte

Answer 21

a solution of ions

Question 22

Lattice Enthalpy

Answer 22

Enthalpy change that accompanies the formation of one mole of an ionic compound from its gaseous ions under standard conditions

• measuring strength of an ionic bond
• exothermic

Question 23

Standard enthalpy change of formation

Answer 23

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
-exo

Question 24

standard enthalpy change of atomisation

Answer 24

enthalpy change that takes place for the formation of one mole of gaseous atoms from the element in its standard state under standard conditions

• endo cuz bonds broken to make gaseous atoms
• then element being atomisaised is already a gas, delta at is related to bond enthalpy of the bond being broken

Question 25

First ionisation energy

Answer 25

energy required to remove an electron from each atom of one gaseous mole of an element to make one gaseous mole of 1+ions.
*endo because energy needed to overcome the attraction between the electron and the positive nucleus

Question 26

first electron affinity

Answer 26

the enthalpy change that takes place when one electron is added to each atom in one mole of gaseous atoms to make one mole of 1- ions.
-exothermic as electron being added is attracted to the nucleus

Question 27

standard enthalpy change of solution

Answer 27

the enthalpy change that takes place when one mole of a compound is completely dissolved in water under standard conditions.
-can be endo or exo

Question 28

standard enthalpy change of hydration

Answer 28

enthalpy change that takes place when one mole of isolated gas ions is dissolved in water forming one mole of aq ions under standard conditions
-exo

Question 29

ionic liquids

Answer 29

ionic compounds that are liquid are room temperature

Question 30

feasibility /spontanuous

Answer 30

the reaction is energetically feasible. if delta g is negative

Question 31

transition elements

Answer 31

d block elements that form at least one ion with a partially filled d orbital

Question 32

coordinate bond

Answer 32

a type of covalent bond when one of the bonded atoms provides both the electrons for the shared pair

Question 33

ligand

Answer 33

molecule or ion that donates a pair of electrons to a central mental ions to form a coordinate bond

Question 34

coordination number

Answer 34

indicates the number of coordinate bonds attached to the central metal ion

Question 35

Monodentate ligand

Answer 35

can donate one pairof electrons to the central metal ion forming 1 coordinate bond

Question 36

bidentate ligand

Answer 36

can donate two pairs of electrons to the central metal ion forming 2 coordinate bonds

Question 37

Ligand substitution

Answer 37

one ligand in a complex ion is replaced by another ligand

Question 38

ppt reaction

Answer 38

two aq solutions contain ions react to make an insoluble ionic solid

Question 39

Buffer solution

Answer 39

system that minimises the change in pH when a small amount of acid or base is added. made of an acid and its conjugate base

Question 40

end point

Answer 40

indicator contains equal con of HA and A-

Question 41

equivalence point

Answer 41

he volume of one solution that exactly reacts with the volume of the othe solution. the centre of the verticle section

Question 42

bronsted lowry acid

Answer 42

proton donor

Question 43

bronsted lowry base

Answer 43

proton acceptor

Question 44

conjugate acid base pair

Answer 44

comtains two species that be interconverted by the transdfer of a proton

Question 45

kw the ionic product of water

Answer 45

1x10-14 at room temp mold2dm-6. [OH-][H+]

Question 46

standard entropy

Answer 46

the entropy of one mole of substance understandard conditions