C7 - acids, bases, and salts

Question 1

What ion do acids release in water?

Answer 1

H⁺ (hydrogen ion)

Question 2

What ion do bases release in water?

Answer 2

OH⁻ (hydroxide ion)

Question 3

What is an alkali?

Answer 3

A base that is soluble in water.

Question 4

What pH value is neutral?

Answer 4

7

Question 5

What pH value indicates an acid?

Answer 5

Less than 7

Question 6

What pH value indicates a base/alkali?

Answer 6

Greater than 7

Question 7

What does the pH scale measure?

Answer 7

The concentration of hydrogen ions (H⁺)

Question 8

What color does red litmus turn in a base?

Answer 8

Blue

Question 9

What color does blue litmus turn in an acid?

Answer 9

Red

Question 10

What color is phenolphthalein in acid and base?

Answer 10

Colorless in acid, pink in base

Question 11

What color is methyl orange in acid and base?

Answer 11

Red in acid, yellow in base

Question 12

What does universal indicator show?

Answer 12

A full range of pH values with different colors

Question 13

Acid + Metal → ?

Answer 13

Salt + Hydrogen

Question 14

Acid + Metal Oxide → ?

Answer 14

Salt + Water

Question 15

Acid + Metal Hydroxide → ?

Answer 15

Salt + Water

Question 16

Acid + Metal Carbonate → ?

Answer 16

Salt + Water + Carbon Dioxide

Question 17

What salt is made from hydrochloric acid?

Answer 17

Chloride

Question 18

What salt is made from sulfuric acid?

Answer 18

Sulfate

Question 19

What salt is made from nitric acid?

Answer 19

Nitrate

Question 20

Magnesium + Sulfuric acid → ?

Answer 20

Magnesium sulfate

Question 21

How can soil acidity be reduced?

Answer 21

By adding quicklime (CaO) or slaked lime (Ca(OH)₂)

Question 22

Why does soil pH need to be controlled?

Answer 22

Some plants grow better in acidic or alkaline soil.

Question 23

What happens to hydrangea color in acidic soil?

Answer 23

They turn blue.

Question 24

What type of oxide is formed by metals?

Answer 24

Basic oxide

Question 25

What type of oxide is formed by non-metals?

Answer 25

Acidic oxide

Question 26

What is a neutral oxide?

Answer 26

An oxide that is neither acidic nor basic (e.g. CO, NO)

Question 27

What is an amphoteric oxide?

Answer 27

One that can react with both acids and bases (e.g. Al₂O₃, ZnO)

Question 28

What is the method for salt preparation with insoluble base?

Answer 28

Add base to acid, filter, and evaporate

Question 29

What is used to prepare a salt from an alkali?

Answer 29

Titration

Question 30

What is a precipitation reaction?

Answer 30

Mixing two solutions to form an insoluble salt

Question 31

Example of a precipitation reaction?

Answer 31

Lead nitrate + Potassium iodide → Lead iodide (yellow ppt)

Question 32

What does hydrated mean?

Answer 32

Contains chemically combined water

Question 33

What does anhydrous mean?

Answer 33

Does not contain water

Question 34

What happens when CuSO₄·5H₂O is heated?

Answer 34

It becomes white anhydrous CuSO₄ and releases water.

Question 35

Is this reaction reversible?

Answer 35

Yes, adding water reforms the blue hydrated crystals.