acids and bases

Question 1

Acids

• what are they?
• three common lab acids

Answer 1

• substances composed of hydrogen atoms chemically bonded to non-metal atoms
• when an acid molecule is added to water it will dissociate into its ions
• strong acids will dissociate completely when come into contact with water, weak acids only release some of their hydrogen ions.
  Common lab acids
• hydrochloric acid
• sulfuric acid
• nitric acid

Question 2

Bases

- what are they?

Answer 2

• substances that remove hydrogen molecules from a solution – metal oxides, hydroxides, carbonates, or hydrogen carbonates.
• Most bases are insoluble
• An alkali is a base that is soluble, they will dissociate when placed in water and create hydroxide ions
• Strong alkalis completely dissociate, weak alkalis partly dissociate.

Question 3

what is concentration?

Answer 3

• a measure of how manty acid/alkali particles there are per unit volume of water.
• higher concentrations are more reactive

Question 4

pH scale

- what is the pH scale

Answer 4

• represents concentration of acids and bases

- pH is a measure of hydrogen/hydroxide ions in a solution

Question 5

Types of indicators

Answer 5

• litmus indicators – blue litmus turns red in a acidic solutions, remains blue in a neutral or basic solution, and vice versa. Litmus paper cannot indicate the strength of solution.
• Universal indicator – shows the strength of the solution through different colours – red = acidic, green = neutral, purple = base

Question 6

What is neutralisation?

Answer 6

• when an acid and base is mixed, the chemical reaction that occurs is called neutralisation – because the result is a neutral solution

Question 7

How are salts formed?

Answer 7

• salts are formed when an acid reacts with metals, bases or carbonates.

Question 8

Neutralisation reaction equation

Answer 8

Acid + base –> salt + water

Question 9

Acid and metal reaction equation

Answer 9

Acid + metal –> salt + hydrogen

Question 10

Acid and metal hydroxide reaction equation

Answer 10

Acid + metal hydroxide –> salt + water

Question 11

Acid and carbonate reaction equation

Answer 11

Acid + carbonate –> salt + carbon dioxide + water

Question 12

Acid and hydrogen carbonate reaction equation

Answer 12

Acid + carbonate –> salt + carbon dioxide + water

Question 13

What is a metal?

Answer 13

an element that forms positive ions (cations) and has metallic bonds.

Question 14

What is a metal hydroxide?

Answer 14

A metal hydroxide forms when a metal reacts with water.

Question 15

What is a carbonate?

Answer 15

a salt of carbonic acid

Question 16

What is a hydrogen carbonate?

Answer 16

a salt of carbonic acid, in which one hydrogen atom has been replaced; an acid carbonate

Question 17

What is an oxide ion?

Answer 17

a chemical compound that contains at least one oxygen atom and one other element in its chemical formula.