Physical Chemistry (Acids, Alkalis, Salts, Energetics, Rates Of Reaction, Equilibria)

Question 1

Universal indicator:
Acid:
Neutral:
Alkali:

Answer 1

Strongly acidic: Red
Weakly acidic: Orange
Neutral: Green
Weakly alkali: Blue
Strongly alkali: Purple

Question 2

Litmus paper:
Acid:
Neutral:
Alkali:

Answer 2

Acid: Red
Neutral: Purple
Alkali: Blue

Question 3

Phenolphthalein:
Acid:
Alkali:

Answer 3

Acid: Colourless
Alkali: Pink

Question 4

Methyl Orange:
Acid:
Alkali:

Answer 4

Acid: Red
Alkali: Yellow

Question 5

Ph 0 =

Answer 5

Strongly acidic

Question 6

Ph 14 =

Answer 6

Strongly acidic

Question 7

An acid is a source of ____________ ions

Answer 7

Hydrogen ions (H+)

Question 8

An alkali is a source of ____________ ions

Answer 8

Hydroxide ions (OH-)

Question 9

The reaction between an acid and an alkali (or an acid and a base) is known as:

Answer 9

Neutralisation

Question 10

Acid + Base–>

Answer 10

Acid + Base–> Salt + Water

Question 11

Acid + Metal Oxide–>

Answer 11

Acid + Metal Oxide–> Salt + Water

Question 12

Acid +Metal Carbonate –>

Answer 12

Acid +Metal Carbonate –> Salt + Water + Carbon dioxide

Question 13

If the acid is hydrochloric acid, the salt will be a metal ___________

Answer 13

Chloride

Question 14

If the acid is sulfuric acid, the salt will be a metal ___________

Answer 14

Sulfate

Question 15

If the acid is nitric acid, the salt will be a metal ___________

Answer 15

Nitrate

Question 16

Everything is soluble except for:

Answer 16

Carbonates (Except for sodium potassium and ammonium)
Barium sulfate
Calcium sulfate
Silver chloride

Question 17

How do you make a soluble salt using acids

Answer 17

Add an insoluble base

Question 18

Describe making a soluble salt using acids + insoluble bases

Answer 18

Add the insoluble base to the acid. The solid will dissolve. The acid had neutralised when the excess solid sinks to the bottom of the flask.
You can then filter out the excess solid to get the salt solution.
For pure, sold crystals of salt, evaporate off the water.

Question 19

How do you make soluble salts from an alkali

Answer 19

Titrations

Question 20

How do you make insoluble salts

Answer 20

Precipitation reaction

Question 21

Describe a precipitation reaction:

Answer 21

Pick two solutions with the ions you need and mix them

Question 22

How do you do a titration

Answer 22

1. Add (25cm3 of) alkali to a conical flask alongside indicator
2. Meanwhile, fill a burette with acid (below eye level)
3. Add the acid to the alkali (using a burette)
4. The indicator will change colour when neutralisation takes place
5. Record the volume of acid used to neutralise the alkali
6. Repeat

Question 23

What four things does a rate of reaction depend on:

Answer 23

Temperature
Concentration (pressure)
Catalyst
Size of particles (surface area)

Question 24

Rate of reaction equation

Answer 24

Rate of reaction = amount of product formed (or reactant used) / Time

Question 25

What are the 3 ways the speed of reaction can be measure

Answer 25

Precipitation Change in mass Volume of gas given off

Question 26

How does a catalyst speed up a reaction

Answer 26

By providing an alternative pathway with lower activation energy

Question 27

What is activation energy

Answer 27

The minimum energy needed by reacting particles for the reaction to occur

Question 28

Chemical reactions in which heat is given out are known as ______________

Answer 28

Exothermic

Question 29

Chemical reactions in which heat is taken in are known as ______________

Answer 29

Endothermic

Question 30

Energy is _____________ to break existing bonds - so bond breaking is an _____________ process

Answer 30

Supplied | Endothermic

Question 31

Energy is _____________ when new bonds are formed - so bond formation is an _____________ process

Answer 31

Released | Exothermic

Question 32

If the value of enthalpy change is negative, the reaction is ______thermic

Answer 32

Exothermic

Question 33

If the value of enthalpy change is positive, the reaction _____thermic

Answer 33

Endothermic

Question 34

In an exothermic energy level diagram, the reactants are __________ the products

Answer 34

Above

Question 35

In an endothermic energy level diagram, the reactants are __________ the products

Answer 35

Below

Question 36

What is a reversible reaction

Answer 36

Where the products of the reactions can themselves react to produce the original reactants

Question 37

Describe the thermal decomposition of ammonium chloride

Answer 37

When heated, ammonium chloride breaks down into ammonia and hydrogen chloride. When the ammonia and hydrogen chloride cool, they re-form to make ammonium chloride

Question 38

What does equilibrium mean

Answer 38

That the relative quantities of reactants and products will reach a certain balance and stay there

Question 39

In a reversible reaction, the position of equilibrium depends on the ____________ and ____________ of the reacting mixture

Answer 39

Temperature and pressure

Question 40

What is the effect of increasing temperature on equilibrium. | What is the effect of decreasing temperature on equilibrium

Answer 40

If you increase the temperature, endothermic reaction will increase (to use up extra heat) If you decrease the temperature, exothermic reaction will increase (to give out more heat)

Question 41

What is the effect of increasing pressure on equilibrium | What is the effect of decreasing pressure on equilibrium

Answer 41

If you increase the pressure, it will encourage the reaction which produces fewer molecules of gas If you decrease the pressure, it will encourage the reaction which produces more molecules of gas

Question 42

What is dynamic equilibrium

Answer 42

The reactions are still taking place in both directions, but the overall effect is nil because they cancel each other out