S2 - Acids and Bases (complete)

Question 1

Acidic

Answer 1

Sour and corrosive. Contains hydrogen. pH < 7.

Question 2

Alkaline

Answer 2

Slippery and soapy. Corrosive. pH >7.

Question 3

Neutral

Answer 3

Neither acidic nor alkaline.

Question 4

pH

Answer 4

A number that describes how acidic something is.

Low pH = acidic.

Question 5

pH scale

Answer 5

A colour scale showing the colours of a pH indicator in different pH.

Question 6

pH indicator

Answer 6

A chemical compound (dye) that changes colour in different pH.

Question 7

Universal indicator

Answer 7

A pH indicator which turns red/orange/yellow in acids, green in neutral solutions and blue/purple in alkalis.

Question 8

Acids or alkalis?

Lemon juice, vinegar, yoghurt

Answer 8

Acids

Question 9

Acids or alkalis?

Bleach, drain cleaner, baking soda

Answer 9

Alkalis

Question 10

Preservative

Answer 10

A substance that stops food from spoiling.

Question 11

Besides flavour, why are acids added to food?

Answer 11

To act as preservatives.

Question 12

What negative effect do acids in food have on your health?

Answer 12

Can cause tooth decay or indigestion.

Question 13

Concentration

Answer 13

The number of stuff/particles dissolved in a liquid.

Question 14

Dilution

Answer 14

Adding water to a solution.

Question 15

When you dilute an acid, the pH ________.

Answer 15

increases

(can go up to 7)

Question 16

When you dilute an alkali, the pH ________.

Answer 16

decreases

(can go down to 7)

Question 17

When you dilute a neutral solution, the pH _______.

Answer 17

does not change

(already 7)

Question 18

Base

Answer 18

A substance that neutralises an acid.

Question 19

Soluble

Answer 19

Dissolves in water.

Question 20

Alkali

Answer 20

A soluble base.

Question 21

Neutralisation

Answer 21

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

Question 22

During neutralisation, the pH of the alkali _______.

Answer 22

drops toward 7

Question 23

During neutralisation, the pH of the acid _______.

Answer 23

rises toward 7

Question 24

Salt

Answer 24

A compound made during neutralisation. It is made when the hydrogen in an acid is replaced with a metal.

Question 25

What types of substances are **bases**?

Answer 25

Metal oxides Metal hydroxides Metal carbonates

Question 26

Parent acid

Answer 26

An **acid** used to make a **salt**.

Question 27

Parent base

Answer 27

A **base** used to make a **salt**.

Question 28

Antacid

Answer 28

**Medicine** to treat **indigestion** which helps **neutralise** stomach acid.

Question 29

Evaporation

Answer 29

**Removing solvent** (liquid) by heating a solution.

Question 30

Acid rain

Answer 30

Rain with pH **lower** than normal.

Question 31

Ocean acidification

Answer 31

The process of **ocean water** becoming **more acidic** over time.

Question 32

**HCl** is a formula for an acid. **How** can we tell this is an **acid**?

Answer 32

Contains **hydrogen**.

Question 33

When is it useful to do a **microscale investigation**?

Answer 33

When the reactants are **expensive**, **toxic** or only available in **small quantities**.

Question 34

Which acid is **stomach acid**?

Answer 34

Hydrochloric acid

Question 35

How do **antacids** work?

Answer 35

They contain a **base** which **neutralises** stomach acid.

Question 36

**Hydrochloric** acid makes ______ salts.

Answer 36

**chloride**

Question 37

**Sulfuric** acid makes ______ salts.

Answer 37

**sulfate**

Question 38

**Nitric** acid makes _______ salts.

Answer 38

**nitrate**

Question 39

**Phosphoric** acid makes ______ salts.

Answer 39

**phosphate**

Question 40

**Potassium chloride** is a **salt** name. Where does the '**potassium**' part come from?

Answer 40

**Parent base** (potassium oxide, hydroxide or carbonate)

Question 41

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

Answer 41

**Parent acid** | (hydrochloric acid)

Question 42

You have a **salt dissolved in water**. What **technique** will let you **separate** the salt and the water?

Answer 42

Evaporation

Question 43

# Fill in the blank:

Answer 43

Question 44

How do you show on this diagram that you are **heating** the mixture?

Answer 44

Question 45

Which **gases** cause **acid rain**?

Answer 45

Sulfur dioxide, nitrogen oxides, carbon dioxide

Question 46

Which **gas** is always produced when **fossil fuels** are **burned**?

Answer 46

Carbon dioxide (CO₂)

Question 47

**Sulfur dioxide** gas can be made when coal is burned. Why is this bad?

Answer 47

Sulfur dioxide is **harmful** to the **respiratory system**, and causes **acid rain**.

Question 48

Where is **nitrogen dioxide** formed?

Answer 48

In **car engines** and **furnaces**.

Question 49

Acid rain is **harmful** to \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_.

Answer 49

**plants and aquatic life**

Question 50

What does **acid rain** do to **rock** and **metal surfaces**?

Answer 50

It **wears away rock** surfaces and **corrodes metal** surfaces.

Question 51

Why are the **oceans** becoming **more acidic**?

Answer 51

Because of **carbon dioxide** **dissolving** in ocean water.