Reactions of Acids (4.2) (M)

Question 1

Acids react with some metals to produce what?

Answer 1

salts and hydrogens

Question 2

What are REDOX reactions?

Answer 2

Reactions where both oxidation and reduction (in terms of electrons) is occurring.

A common example is a displacement reaction

Question 3

What is formed when a metal and hydrochloric acid react?

Answer 3

metal chloride and hydrogen gas

Question 4

What is formed when a metal and sulphuric acid react?

Answer 4

metal sulphate and hydrogen gas

Question 5

Acids are (….) by alkalis and bases

Answer 5

neutralised

Question 6

What is the common example of alkalis?

Answer 6

soluble metal hydroxides

Question 7

What are the common examples of bases?

Answer 7

insoluble metal hydroxides and metal oxides

Question 8

Acids are neutralised by alkalis and bases to produce what?

Answer 8

salts and water

Question 9

Acids can be neutralised by metal carbonates to produce what?

Answer 9

salts, water and carbon dioxide

Question 10

2 needed

The particular salt produced in any reaction between an acid and a base or alkali depends on:

Answer 10

• the acid used (hydrochloric acid produces chlorides, nitric acid produces nitrates, sulfuric acid produces sulfates)
• the positive ions in the base, alkali or carbonate

just need to understand this, just set it to level 5 once understood

Question 11

How can soluble salts be made?

Answer 11

By reacting acids with solid insoluble substances, such as metals, metal oxides, hydroxides or carbonates

Question 12

Describe the physical process to making soluble salts

Answer 12

The solid insoluble substance (metals, metal oxides, hydroxides or carbonates) is added to the acid until no more reacts and the excess solid is filtered off to produce a solution of the salt.

Question 13

How can salt solutions be made into solid salts?

Answer 13

by crystallising them

Question 14

Acids produce (…) ions in (…)

Answer 14

Hydrogen ions (H⁺)

aqueous solutions

Note: they produce the ions, must be in aqueous solution

Question 15

(…) of alkalis contain (…) ions

Answer 15

aqueous solutions

hydroxide (OH^–)

Note: they only contain (do not produce as per acids) the ions, must be in aqueous solution

Question 16

What are the range of values for the pH scale?

Answer 16

0 to 14

Question 17

What is the pH scale?

Answer 17

a measure of the acidity or alkalinity of a solution

Question 18

How can the pH scale be measured?

Answer 18

using universal indicator or a pH probe

Question 19

What pH value will a neutral solution have?

Answer 19

pH 7

Question 20

What pH value will an acidic solution have?

Answer 20

less than pH 7

Question 21

What pH value will an alkaline solution have?

Answer 21

more than pH 7

Question 22

What happens in neutralisation reactions between an acid and an alkali (in terms of ions)?

Answer 22

hydrogen ions react with hydroxide ions to produce water

Question 23

What is the (ionic) equation for a neutralisation reaction?

Answer 23

H⁺ + ^–OH ⇢ H₂O

Question 24

What are the colours of the pH scale?

Answer 24

Acids - red

Alkalis - blue (or purple)

Neutral - green

Question 25

How can the volumes of acid and alkali solutions that react with each other be measured?

Answer 25

by titration using a suitable indicator (e.g. phenolphthalein turns pink in alkaline solutions)

Question 26

3 needed

What are examples of strong acids?

Answer 26

• sulfuric acids
• hydrochloric acids
• nitric acids

Question 27

What are concordant titres?

Answer 27

Titres (volume results from titrations) within 0.10 cm³ of each other

Question 28

Why do we use concordant titres/results?

Answer 28

to identify and remove anomalous results, so it is more precise/accurate

Question 29

What is a strong acid?

Answer 29

An acid that is completely ionised in aqueous solution

Question 30

3 needed

What are examples of strong acids?

Answer 30

hydrochloric, nitric and sulfuric acids

Question 31

What is a weak acid?

Answer 31

An acid that is only partially ionised in aqueous solution

Question 32

3 needed

What are examples of weak acids?

Answer 32

ethanoic, citric and carbonic acids

Question 33

For a the same concentration of aqueous solutions, the stronger an acid, the (…) the pH.

Answer 33

lower

Question 34

As the pH decreases by one unit, the hydrogen ion concentration of the solution increases by a factor of (…)

Answer 34

10 - scale is logarithmic

Question 35

What are dilute and concentrated solutions of acids?

Answer 35

Concentrated - high percentage of solution is acid

Dilute - low percentage of solution is acid (rest is usually water)

Question 36

What is the H⁺ concentration for pH 0, 3 and 6

Answer 36

pH 0 - 1

pH 3 - 1 x 10^-3

pH 6 - 1 x 10^-6

Question 37

How can an acid be described as both strong and dilute?

Answer 37

Strong acid as it completely ionises in water

Dilute as there is small amount of acid per unit volume

Question 38

What is an alkali?

Answer 38

a base that dissolves in water

• to produce an alkaline solution with a pH greater than 7*
• other bases may be insoluble*

Question 39

If the reaction is reversible, the acid is…

Answer 39

weak

Question 40

Alcohol is a (…) acid

Answer 40

weak

as ethanoic acid present