Chapter 4-Acids and redox

Question 1

What does an acid+metal oxide make?

Answer 1

Salt+water

Question 2

What does an acid+alkali make?

Answer 2

Salt+water

Question 3

What does an acid+metal carbonate make?

Answer 3

Salt+carbon dioxide+water

Question 4

What do all acids contain and what state are they in?

Answer 4

• H⁺ ions
• (aq) state

Question 5

What happens to acids in water?

Answer 5

They release their H⁺ ions (proton donors) making them an acid

Question 6

What is every molecule of a strong acid split up into?

Answer 6

A H⁺ ion and a negative ion

Question 7

What makes a strong acid?

Answer 7

It fully dissociates in water

Question 8

What makes a weak acid?

Answer 8

It only partially dissociates in water

Question 9

What is the formula for a weak acid dissociating?

Answer 9

H𝑥⇌H⁺+𝑥⁻

Question 10

What are some examples of strong acids?

Answer 10

• Phosphoric acid
• Hydrochloric acid
• Sulfuric acid
• Nitric acid

Question 11

What are some examples of weak acids?

Answer 11

• Citric acid
• Ethanoic acid

Question 12

What are bases?

Answer 12

Substances that neutralise an acid and form a salt

Question 13

What is an alkali?

Answer 13

A base that dissolves in water releasing OH⁻ ions

Question 14

What are alkalis called?

Answer 14

Proton acceptors

Question 15

What are examples of types of bases?

Answer 15

• Carbonates
• Oxides
• Hydroxides

Question 16

What is a standard solution?

Answer 16

A solution of known concentration

Question 17

What colour does a basic solution turn when phenolphthalein is added?

Answer 17

Pink

Question 18

What colour does an acidic solution turn when phenolphthalein is added?

Answer 18

Colourless

Question 19

What colour does a basic solution turn when methyl orange is added?

Answer 19

Yellow

Question 20

What colour does an acidic solution turn when methyl orange is added?

Answer 20

Red

Question 21

What colour does a neutral solution turn when methyl orange is added?

Answer 21

Orange

Question 22

What is the accuracy of a burette?

Answer 22

0.05cm³

Question 23

What are concordant titres?

Answer 23

Titres that are within 0.10cm³ of each other

Question 24

When does the indicator change colour?

Answer 24

The end point of a reaction

Question 25

In a titration what is used to measure the unknown solution?

Answer 25

A volumetric pipette and pipette filler

Question 26

How is a colour change more easily spotted?

Answer 26

By placing a white tile underneath the conical flask

Question 27

What is an accurate method of weighing called?

Answer 27

Weighing by difference

Question 28

What is a standard solution measured in?

Answer 28

A volumetric flask

Question 29

What helps avoid systematic errors?

Answer 29

Being in eye level with the equipment and reading from the bottom of the meniscus

Question 30

What does oxidation involve?

Answer 30

* Loss of electrons * Gaining oxygen * Losing hydrogen * Increase in ox. no.

Question 31

What does reduction involve?

Answer 31

* Gain of electrons * Loss of oxygen atoms * Gaining hydrogen * Decrease in ox. number

Question 32

What is an oxidation number?

Answer 32

The number of electrons an atom uses to bond with any other atom

Question 33

What are the oxidation number rules?

Answer 33

1) On simple ions the oxidation state is the charge on the ion 2) In elements the oxidation state is always 0 3) The total of all the oxidation states must equal the overall charge on the species 4) In molecules and more complex ions, the more electronegative element is assumed to be the negative ion 5) H is nearly always +1 and oxygen -2 6) The sign is written before the oxidation number not after

Question 34

What is the oxidation state of Group 1 metals?

Answer 34

Always +1

Question 35

What is the oxidation state of Group 2 metals?

Answer 35

Always +2

Question 36

What is the of oxidation state Oxygen?

Answer 36

Usually -2 except in peroxides e.g. H₂O₂ where it is -1 and F₂O where it is +2

Question 37

What is the oxidation state of Hydrogen?

Answer 37

Usually +1 except in metal hydrides where it is -1

Question 38

What is the oxidation state of Flourine?

Answer 38

Always -1

Question 39

What is the oxidation state of Chlorine?

Answer 39

Usually -1 except in compounds with O or F

Question 40

What is the oxidation number of a metal?

Answer 40

Shown by the number of roman numerals

Question 41

What is it called when the same species is oxidised and reduced in the same reaction?

Answer 41

Disproportionation

Question 42

What is the Oxidising agent?

Answer 42

The species that is reduced

Question 43

What is the Reducing agent?

Answer 43

The species that is oxidised