U1-3 - Acids and Bases

Question 1

What is pH?

Answer 1

A number that measures how acidic or alkaline something is.

(Usually 0–14)

Question 2

Acidic solutions have pH…

Answer 2

less than 7.

Question 3

Alkaline solutions have pH…

Answer 3

more than 7.

Question 4

Neutral solutions have pH…

Answer 4

equal to 7.

Question 5

Colour of universal indicator in neutral solutions

Answer 5

Green

Question 6

Colour of universal indicator in alkalis

Answer 6

Blue/purple

Question 7

Colour of universal indicator in acid

Answer 7

Red

(red/orange/yellow)

Question 8

Ions which make a solution acidic

Answer 8

H⁺ (hydrogen)

Question 9

Ions which make a solution alkaline

Answer 9

OH^– (hydroxide)

Question 10

Formula for hydrochloric acid

Answer 10

HCl

Question 11

Formula for sulfuric acid

Answer 11

H₂SO₄

Question 12

Formula for nitric acid

Answer 12

HNO₃

Question 13

Acid

Answer 13

Substance which contains hydrogen ions (H⁺)

Question 14

Alkali

Answer 14

Substance which contains hydroxide ions (OH^–)

Question 15

Why is water neutral?

Answer 15

Equal numbers of H⁺ and OH^– ions.

Question 16

Formula for phosphoric acid

Answer 16

H₃PO₄

Question 17

If an alkali is diluted, the pH …

Answer 17

decreases.

Question 18

If an acid is diluted, the pH …

Answer 18

increases.

Question 19

If a solution is diluted, the concentrations of H⁺ and OH^– ions …

Answer 19

decrease.

Question 20

If a solution is diluted, the pH moves towards…

Answer 20

7.

(it cannot go past 7)

Question 21

Soluble metal oxides turn solution pH…

Answer 21

alkaline.

Question 22

Soluble non-metal oxides turn solution pH…

Answer 22

acidic.

Question 23

Insolube oxides turn solution pH…

Answer 23

neutral (no effect).

Question 24

Environmental problems caused by non-metal oxide gases

Answer 24

Acid rain, ocean acidification, greenhouse effect.

Question 25

Gases which cause **acid rain**

Answer 25

Carbon dioxide, sulfur dioxide, nitrogen oxides

Question 26

Neutralisation

Answer 26

A reaction between an **acid** and a **base** which produces a **salt** and **water**.

Question 27

Base

Answer 27

A substance which can **neutralise an acid**

Question 28

Salt

Answer 28

A compound made when the **hydrogen** ions in an **acid** are replaced by **metal ions**.

Question 29

Metal …., ….and … are **bases**.

Answer 29

Metal **oxides**, **hydroxides** and **carbonates** are **bases**.

Question 30

Metal hydroxide + Acid → ...

Answer 30

Salt + Water

Question 31

A compound made when the **hydrogen** ions in an **acid** are replaced by **metal ions**.

Answer 31

Salt

Question 32

**Sulfuric** acid makes .... salts.

Answer 32

**sulfate**

Question 33

**Hydrochloric** acid makes .... salts.

Answer 33

**chloride**

Question 34

What is the **difference** between a **base** and an **alkali**?

Answer 34

Both neutralise acids, but an alkali must also be **soluble in water**

Question 35

Metal oxide + Acid → ...

Answer 35

Salt + Water

Question 36

Metal carbonate + Acid → ...

Answer 36

Salt + Water + **Carbon dioxide**

Question 37

Soluble base

Answer 37

Alkali

Question 38

**Sodium chloride** is a salt. Where does the '**sodium**' part come from?

Answer 38

**Parent base** | (sodium oxide, hydroxide or carbonate)

Question 39

**Sodium chloride** is a salt. Where does the '**chloride**' part come from?

Answer 39

**Parent acid** | (hydrochloric acid)

Question 40

**Phosphoric** acid makes .... salts.

Answer 40

**phosphate**

Question 41

**Nitric** acid makes .... salts.

Answer 41

**nitrate**

Question 42

Colour of **phenolphthalein** in **alkaline** solutions

Answer 42

**Pink**

Question 43

An insoluble **metal carbonate** reacts with an **acid**. How do you know the reaction is **finished**?

Answer 43

**Effervescence** (fizzing) has stopped.

Question 44

Lab technique used to **separate** a **solid** from a **liquid**.

Answer 44

Filtration

Question 45

Lab technique used to **separate** a **dissolved solid** from a **liquid**.

Answer 45

Evaporation

Question 46

Why are **acids** added to **food**?

Answer 46

To **improve flavour** or to act as **preservatives**

Question 47

Preservative

Answer 47

A substance which **prevents food from spoiling** (e.g. ascorbic acid)

Question 48

**Negative** effects of consuming **too much** acidic food/drink

Answer 48

Tooth decay, indigestion

Question 49

Colour of **phenolphthalein** in **acidic** and **neutral** solutions

Answer 49

**Colourless** | (NOT clear!)

Question 50

What is the point of **titration**?

Answer 50

To find out an **unknown** concentration.

Question 51

During a titration, what tells you the reaction is **finished**?

Answer 51

The **first permanent** colour change