Unit C Section 1.2

Question 1

acid

Answer 1

An acid is a compound that dissolves in water to form a solution with a pH lower than 7.

Question 2

pH

Answer 2

The pH number of a solution indicates its acidity.

It is a measure of the concentration of hydrogen ions in a solution.

Question 3

base

Answer 3

A base is a compound that dissolves in water to form a solution with a pH higher than 7

Question 4

What is sulfuric acid?

Answer 4

Sulfur dioxide combines with water to form sulfuric acid.

Question 5

What is nitric acid?

Answer 5

Nitrogen oxides combine with

water to form nitric acid.

Question 6

What is Carbon dioxide?

Answer 6

Carbon dioxide dissolves in water to form

carbonic acid

Question 7

How are acids produced?

Answer 7

-Industrial processes and fuel combustion produce large quantities of carbon dioxide, sulfur dioxide, and nitrogen oxides. In the air, these chemicals dissolve in water droplets to form acids

Question 8

How is acidity measured and in what ranges?

Answer 8

Acidity is measured according to the pH scale. Most solutions have a pH in the range of 0 to 14.

• A solution with a pH of 0 is very acidic
• A solution with a pH of 14 is very basic or alkaline
• A pH of 7 means that a solution is neutral—it’s neither an acid nor a base.

Question 9

What is the difference between each unit of measurement in the pH is scale?

Answer 9

a solution with a pH of 3 is 10 times more acidic than a solution with a pH of 4

Question 10

Different products on the pH scale:

Answer 10

0.5= battery acid
1.0= stomach acid
2.0= lemon juice
2.2= vinegar
4.0= most animals are dead
4.2= tomatoes
5.6= normal rain
6.0= milk
7.0= distilled water
8.0= some soils and lakes in Alberta
8.2= baking soda
10= toothpaste
12= ammonia
13.8= drain cleaner

Question 11

Acid-base indicators are substances that can change colour when they are placed in solutions.

What color indicates which measure?

Answer 11

• blue litmus paper turns red in an acid

- red litmus paper turns blue in a base

Question 12

What is a universal indicator?

Answer 12

A universal indicator is a mixture of indicators that change colour over a wide pH range. The pH of
a clear fluid can be identified by the colour of the fluid after several drops of the indicator have been added.

Question 13

What is an antacid?

Answer 13

An antacid is a mild base that reacts with the acid in your stomach to neutralize it. The base in the antacid and the acid in your stomach react to form compounds that are less upsetting to your stomach.

Question 14

What is neutralization?

Answer 14

An acid-base reaction that makes the substance neutral

Question 15

The neutralization reaction produces:

Answer 15

The neutralization reaction produces

water and a compound called a salt

Question 16

Neutralization formuala:

Answer 16

acid + base → salt + water

Question 17

pH of ordinary rain water:

Answer 17

naturally slightly acidic

The raindrops dissolve carbon dioxide from the air to form very weak carbonic acid, which has a pH of about 5.6

Question 18

How are acidic lakes neutralized?

Answer 18

Acidic lakes are sometimes treated with lime (calcium hydroxide) to neutralize them.

Question 19

What happens when acidic lakes are treated with lime?

Answer 19

• A chemical reaction takes place between this limewater, which is a base, and the dilute sulfuric acid of the lake’s water
• The reaction produces calcium sulfate (a salt) and water

Question 20

formula for acidic water + lime?

Answer 20

calcium hydroxide + sulfuric acid → calcium sulfate + water