Physical Chemistry

Question 1

What is the pH / colour of strongest acid ?

Answer 1

0 red

Question 2

What is the pH / colour of strongest alkali ?

Answer 2

14 purple

Question 3

What is the pH / colour of neutral substance?

Answer 3

7 green

Question 4

State the colour of litmus paper - acid

Answer 4

red

Question 5

State the colour of litmus paper - neutral

Answer 5

purple

Question 6

State the colour of litmus paper - alkali

Answer 6

blue

Question 7

State the colour of phenolphthalein - acid

Answer 7

colourless

Question 8

State the colour of phenolphthalein - alkali

Answer 8

bright pink

Question 9

State the colour of methyl orange - acid

Answer 9

red

Question 10

State the colour of methyl orange - alkali

Answer 10

yellow

Question 11

Describe acids

Answer 11

source of hydrogen ions (H+)

pH of less than 7

Question 12

What is a base?

Answer 12

substance that can neutralise an acid

alkalis are soluble bases

Question 13

Describe alkalis

Answer 13

source of hydroxide ions (OH-)

pH greater than 7

Question 14

what is a neutralisation reaction ?

Answer 14

reaction between acid + base
(or acid + alkali)
ends with pH of 7

Question 15

Acid + Base ——

Answer 15

—– salt + water

Question 16

what is the neutralisation reaction between H+ and OH-?

Answer 16

H+ + OH- — H²O

Question 17

Acid + Metal Oxide —

Answer 17

Salt + Water

Question 18

Acid + Metal Carbonate —

Answer 18

Salt + Water + Carbon Dioxide

Question 19

what is soluble ?

Answer 19

dissolvable

Question 20

what is insoluble ?

Answer 20

won’t dissolve

Question 21

State the soluble salts

Answer 21

sodium, potassium, ammonium
Nitrates
Chlorides - except silver chloride
Sulfates - except barium sulfate and calcium sulfate

Question 22

State the insoluble salts

Answer 22

Silver chloride, barium / calcium sulfate

Carbonates - except sodium, potassium, ammonium carbonates

Question 23

State the insoluble bases

Answer 23

most metal oxides, metal carbonates and metal hydroxides

Question 24

What are the factors for the rate of a reaction?

Answer 24

Temperature
Concentration
Catalyst
Surface area

Question 25

Rate of reaction =

Answer 25

Amount of reactant or product / time

Question 26

what is activation energy ?

Answer 26

the energy needed to break the initial bonds for particles to react when then collide

Question 27

How do reactions occur?

Answer 27

when particles collide with enough energy

Question 28

How does a higher temperature increase rate of reaction?

Answer 28

particles gain energy, therefore gain speed, increasing number of collisions and gives them enough power for the activation energy

Question 29

How does a higher concentration (or pressure) increase rate of reaction?

Answer 29

this increases the number of reactants, increasing number of collisions until the point where there are fewer reactant particles (slows down)

Question 30

How does a larger surface area increase rate of reaction?

Answer 30

If reactant is a solid, the more divided it is, the larger the surface area. This means surrounding particles have more area to work on, increasing collisions

Question 31

How does a catalyst increase rate of reaction?

Answer 31

Provides particles with an alternate route with a lower activation energy, meaning more particles can react

Question 32

What is the type of reaction for bond breaking ?

Answer 32

endothermic, as energy needed to break bonds

Question 33

What is the type of reaction for bond making ?

Answer 33

exothermic, as energy released when bonds formed

Question 34

Define an exothermic reaction

Answer 34

a reaction which gives out energy to the surroundings, usually in the form of heat and usually shown in a rise in temperature

Question 35

Define an endothermic reaction

Answer 35

a reaction which takes in energy from the surroundings, usually in the form of heat and usually shown by a fall in temperature

Question 36

Define enthalpy change

Answer 36

The overall change in energy in a reaction

Question 37

What is the symbol for enthalpy change ?

Answer 37

ΔH Δ means 'change in' H means enthalpy

Question 38

What is the unit for enthalpy change ?

Answer 38

kJ/mol

Question 39

What is the reaction when the enthalpy change is negative ?

Answer 39

exothermic (giving out energy)

Question 40

What is the reaction when the enthalpy change is positive ?

Answer 40

endothermic (taking in energy)

Question 41

describe a titration

Answer 41

using pipette and pipetter filter, add alkali to flask with phenolphthalein fill burette with acid using burette, slowly add acid to alkali give regular swirls once alkali turns pink, record volume of acid used repeat (reliability)

Question 42

making soluble salts

Answer 42

add insoluble base to acid filter excess base evaporate water to get crystals

Question 43

making insoluble salts

Answer 43

(precipitation reaction) pick two solutions with the ions needed mix ions and filer insoluble salt

Question 44

what is a reversible reaction ?

Answer 44

reaction where the products of the reaction can themselves react to form the reactants

Question 45

what is dynamic equilibrium ?

Answer 45

reactions are taking place at the same time in both directions

Question 46

what is just equilibrium ?

Answer 46

relative (%) quantities of reactants and products

Question 47

how does temperature change equilibrium ?

Answer 47

(all reactions are exo one way and endo the other) high temp - endo reaction increases to use extra heat low temp - exo reaction increases to give out heat

Question 48

how does pressure change equilibrium ?

Answer 48

(most gas reactions have more molecules one side) pressure rise - increase reaction with less molecules pressure drop - increase reaction with more molecules

Question 49

what is 1cm3 of water the same as ?

Answer 49

1g of water