chem chap 8 - acids and bases

Question 1

What is an acid?

Answer 1

A substance that produces hydrogen ions (H+) in aqueous solutions

Question 2

What is the formulae of hydrochloric acid, nitric acid and sulfuric acid and what ions do they produce in aqueous solutions?

Answer 2

HCl, HNO3, H2SO4
Cl- NO3- SO4 2-

Question 3

What are the 3 properties of acids?

Answer 3

Sour taste, acids dissolve in water to form solutions that conduct electricity and turns blue litmus paper red

Question 4

What are the 3 reactions of acids?

Answer 4

acid + metal -> salt + hydrogen
acid + carbonate -> salt + water + carbon dioxide
acid + base -> salt + water

Question 5

What are salts?

Answer 5

An ionic compound that can be obtained from acidic reactions

Question 6

What salt is formed in a reaction involving sulfuric acid?

Answer 6

Sulfate

Question 7

What salt is formed in a reaction involving nitric acid?

Answer 7

Nitrate

Question 8

What salt is formed in a reaction involving hydrochloric acid?

Answer 8

Chloride

Question 9

In the word equation: magnesium + dilute sulfuric acid → magnesium sulfate + hydrogen
Label the reactive metal, acid, cation, salt

Answer 9

Reactive metal: magnesium
Acid: dilute hydrochloric acid
Cation: magnesium
Salt: sulfate

Question 10

What is the test for hydrogen gas?

Answer 10

Placing a burning splint at the mouth of the test tube, hydrogen gas extinguishes the burning splint with a “pop” sound

Question 11

In this word equation: calcium carbonate + hydrochloric acid → calcium chloride + carbon dioxide + water
Label the carbonate, acid, cation and salt

Answer 11

Carbonate: calcium carbonate
Acid: hydrochloric acid
Cation: calcium
Salt: chloride

Question 12

What is the test for carbon dioxide gas?

Answer 12

Bubbling the gas through limewater. Carbon dioxide gas forms a white precipitate with limewater

Question 13

In this word equation: magnesium hydroxide + dilute nitric acid → magnesium nitrate + water
Label the reactant cation, hydroxide, product cation, salt

Answer 13

Reactant cation: magnesium
Hydroxide: magnesium hydroxide
Product cation: magnesium
Salt: nitrate

Question 14

What is a base?

Answer 14

A metal oxide or hydroxide. They contain the oxide ion (O 2-) or the hydroxide ion (OH-)

Question 15

What are the properties of a base?

Answer 15

Most bases are insoluble in water ( not alkalis)
When an acid reacts with a base, neutralisation reaction occurs

Question 16

What are alkalis?

Answer 16

Bases that are soluble in water
A substance that produces hydroxide ions, OH-, in aqueous solutions

Question 17

What are the properties of an alkali?

Answer 17

Taste bitter, feel slippery and soapy, dissolves in water to form solutions that conduct electricity, turn red litmus paper blue, when heated with ammonium salts give off ammonia gas, react with acids to form salt and water

Question 18

What is the general equation of ammonium salts reacting with alkali

Answer 18

Alkali + ammonium salt → salt+ water+ ammonia gas

Question 19

What is the test for ammonia gas?

Answer 19

Ammonia gas turns damp red litmus paper blue in alkali + ammonium salt solution

Question 20

what colour would these indicators be in acidic solutions?
Methyl orange, screened methyl orange, litmus, thymolphtalein

Answer 20

Methyl orange: red
Screened methyl orange: violet
Litmus: red
Thymolphtalein: colourless

Question 21

what colour would these indicators be in alkaline solutions?
Methyl orange, screened methyl orange, litmus, thymolphtalein

Answer 21

Methyl orange: yellow
Screened methyl orange: green
Litmus: blue
Thymolphtalein: blue

Question 22

At what pH range which these indicators change colour?
Methyl orange, screened methyl orange, litmus, thymolphtalein

Answer 22

3 to 5, 3 to 5, 5 to 8, 9 to 10.5

Question 23

At which numbers of the pH scale is acidic, neutral, alkaline

Answer 23

Acidic: 0 to 6
Neutral: 7
Alkaline: 8 to14

Question 24

Describe the concentration of hydrogen ions and hydroxide ions in an acidic solution

Answer 24

More hydrogen ions than hydroxide ions

Question 25

Describe the concentration of hydrogen ions and hydroxide ions in a neutral solution

Answer 25

Hydrogen ions equal to hydroxide ions

Question 26

Describe the concentration of hydrogen ions and hydroxide ions in an alkaline solution

Answer 26

Less hydrogen ions than hydroxide ions

Question 27

What happens when there are low pH values in soil?

Answer 27

There is a decrease inte uptake of phosphorus and potassium Lack of phosphorus causes the leaves to turn dark green Earn of potassium causes the leaves to turn yellow

Question 28

What is ste typical pH level of soil

Answer 28

4 to 8: most plants grow best when soil is neutral or slightly acidic

Question 29

Now does ph of soil become unsuitable for plants?

Answer 29

Too much fertiliser added to soil Environmental pollution such as acid rain

Question 30

How to control the pH of the soil?

Answer 30

Chemicals are often added to soil to adjust pH levels Soil that is too acidic can be treated with bases such as slaked time (calcium hydroxide) other wise known as liming the soil Calcium hydroxide reacts with the acid in the soil and increases the pH so that plants can grow healthily

Question 31

What happens when too much calcium hydroxide is added to soil

Answer 31

The soil will be too alkaline which is unsuitable for plant growth

Question 32

What are the properties of basic oxides (metal oxides)

Answer 32

Most are insoluble in water Solids at room temperature Read with acids to form salt and water

Question 33

What are amphoteric oxides?

Answer 33

Metallic oxides that react with both acids and bases to form salts and water

Question 34

In the word equation: hydrochloric acid + zinc oxide → zinc chloride + water, does the metal oxide, zinc oxide but as a basic oxide / base or acidic oxide / acid?

Answer 34

Basic oxide

Question 35

In the word equation: sodium hydroxide + zinc oxide → sodium zincate + water, does the metal oxide, zinc oxide but as a basic oxide / base or acidic oxide / acid?

Answer 35

Acidic oxide

Question 36

What are the properties of acidic oxides?

Answer 36

Most acidic oxides dissolve in water to form acids Acidic oxides do not react with acids

Question 37

What are neutral oxides

Answer 37

Non-metals that form oxides that show neither basic nor acidic properties

Question 38

Are neutral oxides soluble in water?

Answer 38

Insoluble

Question 39

This oxide reacts with acids but reacts with alkalis, what oxide is this?

Answer 39

Amphoteric

Question 40

This oxide reacts with acids and does not react with alkalis, what oxide is this?

Answer 40

Basic oxides

Question 41

This oxide does not react with acids but reacts with alkalis, what oxide is this

Answer 41

Acidic oxides

Question 42

This oxide does not react with acids and does not react with alkalis, what oxide is this

Answer 42

Neutral oxide