Chemistry June

Question 1

Arrhenius acid/base

Answer 1

substance that produces hydrogen ions when dissolved in water vs produces hydroxide ions

Question 2

Bronsted acid/base

Answer 2

Acid is a proton donor and a base is a proton acceptor

Question 3

strong acid

Answer 3

ionises completely in water to form a high concentration of hydronium ions

Question 4

strong base

Answer 4

dissociates completely in water to form a high concentration of hydroxide ions

Question 5

concentrated acid

Answer 5

contains a large amount of acid in proportion to the volume of water

Question 6

ampholyte

Answer 6

substance that can act as an acid or a base

Question 7

hydrolysis

Answer 7

reaction of a salt with water

Question 8

equivalence point

Answer 8

point at which the acid and base have completely reacted with each other

Question 9

auto ionisation

Answer 9

reaction of water with itself to form hydronium and hydroxide ions

Question 10

redox reaction

Answer 10

involves the electron transfer from one substance to another

Question 11

heat of a reaction

Answer 11

energy absorbed or released in a chemical reaction

Question 12

activation energy

Answer 12

minimum energy required for a reaction to take place

Question 13

reaction rate

Answer 13

change in concentration of reactants or products per unit time

Question 14

chemical equilibrium

Answer 14

a stage in a reversible chemical reaction when the rate of the forward reaction is equal to the rate of the reverse reaction

Question 15

dynamic chemical equilibrium

Answer 15

a stage in a reversible chemical reaction when the rate of the forward reaction is equal to the rate of the reverse reaction and both the forward and reverse reactions are occurring continuously and simultaneously

Question 16

what affects reaction rate

Answer 16

temperature, surface area, concentration, catalyst

Question 17

what disturbs chemical equilibrium

Answer 17

concentration, temperature, pressure (increasing/decreasing volume)

Question 18

le chateliers principle

Answer 18

when the equilibrium in a closed system is disturbed the system will reinstate a new equilibrium by favouring the reaction that will oppose the disturbance

Question 19

what happens when pressure is increased (V is decreased)

Answer 19

the reaction that forms the least amount of gaseous moles of substance will be favoured

NB: when the pressure is increased, both the forward and reverse reaction rates increase because concentration of all reagents increases

If the no. of moles of gaseous reactants equals that of the products, no reaction will be favoured

Question 20

what happens when you add a catalyst to a reaction in chem. E

Answer 20

Eq is not disturbed, forward and reverse reaction rates increase equally

Question 21

What changes the Kc value

Answer 21

temperature only

Question 22

what happens when you add a catalyst to a reaction in relation to a graph

Answer 22

forward and reverse reaction rates increase equally, gradient of all curves is steeper and equilibrium is reached sooner

Question 23

galvanic cell

Answer 23

cell in which chemical energy is converted in to electrical energy

Question 24

anode

Answer 24

the electrode where oxidation takes 1

Question 25

cathode

Answer 25

electrode where reduction takes place

Question 26

function of salt bridge

Answer 26

completes the circuit
maintains electrical neutrality

Question 27

Functions of inert Pt electrode

Answer 27

conducts the electrons
provides a surface for the reaction to occur

Question 28

hydrogen electrode conditions

Answer 28

electrolyte concentration of 1
Temperature of 25
Pressure of 1 atmosphere

Question 29

cracking

Answer 29

chemical process where longer chain hydrocarbons are broken down into smaller more useful molecules

Question 30

electrolyte

Answer 30

solution that conducts electricity through the movement of ions.

Question 31

electrolytic cell

Answer 31

cell in which electrical energy is converted into chemical energy

Question 32

electrolysis

Answer 32

process where electrical energy is used to produce a chemical change

Question 33

combustion

Answer 33

reaction of a compound with oxygen