7.1 - Acids and Bases

Question 1

What are acids? [2]

Answer 1

• substances that release hydrogen ions when dissolved in water
• resulting in a pH less than 7

Question 2

What is pH? [2]

Answer 2

• a number
• shows how acidic or basic a solution is

Question 3

What are bases? [2]

Answer 3

• substances that release hydroxide ions when dissolved in water
• resulting in a pH greater than 7

Question 4

What is the reaction between acid + metal? [2]

Answer 4

acid + metal –> salt + hydrogen gas

Question 5

What is the reaction between acid + base? [2]

Answer 5

acid + base –> salt + water

Question 6

What is the reaction between an acid + base called and what is it? [2]

Answer 6

• neutralisation
• chemical reaction

Question 7

What is the reaction between acid + carbonate? [2]

Answer 7

acid + carbonate –> salt + water + carbon dioxide

Question 8

What is a Base? [2]

Answer 8

• usually oxides or hydroxides of metals

Question 9

What are alkalis? [1]

Answer 9

• bases that are soluble in water

Question 10

What is the reaction between base + acid? [2]

Answer 10

base + acid –> salt + water

Question 11

What is the reaction between base + ammonium salts? [2]

Answer 11

base + ammonium salt –> salt + water + ammonia gas

Question 12

What are acids defined as? [1]

Answer 12

proton donors

Question 13

What are alkalis defined as? [1]

Answer 13

proton acceptors

Question 14

What type of bonding is expected in acids? [1]

Answer 14

covalent bonds

Question 15

What type of bonding is expected in alkalines? [1]

Answer 15

ionic bonds

Question 16

What is an ionic bond? [2]

Answer 16

the electrostatic force of attraction between oppositely charged ions

Question 17

What is a covalent bond? [2]

Answer 17

shared pair of electrons between two atoms

Question 18

All ___ are ___ but not all ___ are ___. [4]

Answer 18

• alkalis
• bases
• bases
• alkalis

Question 19

What is the pH for acids? [1]

Answer 19

<7

Question 20

What is the pH for alkalines? [1]

Answer 20

> 7

Question 21

Why is a H+ ion a proton? [2]

Answer 21

• hydrogen atom has one proton and one electron
• when it loses the electron only the proton is left

Question 22

What is a strong acid? [2]

Answer 22

• an acid that completely dissociates in an aqueous solution
• all of its molecules break apart into ions

Question 23

What is a weak acid? [2]

Answer 23

• an acid that only partially dissociates in an aqueous solution
• only some of its molecules break apart into ions

Question 24

What is an example of a strong and weak acid? [2]

Answer 24

• strong: HCl
• weak: ethanoic acid

Question 25

What is universal indicator? [2]

Answer 25

• a substance that changes colour
• shows how acidic or alkaline a solution is

Question 26

How are the H+ concentration related to the acid strength and the pH? [3]

Answer 26

• the higher the hydrogen ion concentration
• the stronger the acid
• the lower the pH

Question 27

How are the OH- concentration related to the alkali strength and the pH? [3]

Answer 27

• the higher the hydroxide ion concentration
• the stronger the alkali
• the higher the pH

Question 28

How do we compare the neutrality, relative acidity and relative alkalinity using universal indicator? [2]

Answer 28

• add a drop of universal indicator into the substance to be tested
• compare its colour change to the pH colour chart

Question 29

What does it mean if a substance is neutral? [3]

Answer 29

• turns green
• equal concentrations of H+ ions and OH- ions
• pH 7

Question 30

What is the equation for neutralisation? [1]

Answer 30

H⁺ + OH⁻ –> H₂O