9F-Chemical Reactions

Question 1

What is a chemical formula?

Answer 1

The make up of what atoms are inside a compound.

Chemical formulas represent the composition of substances, indicating the elements present and their proportions.

Question 2

What is the chemical formula of water?

Answer 2

H2O

Water is composed of two hydrogen atoms and one oxygen atom.

Question 3

What is the chemical formula of carbon dioxide?

Answer 3

CO2

Carbon dioxide consists of one carbon atom and two oxygen atoms.

Question 4

What is the chemical formula of oxygen?

Answer 4

O2

Oxygen is diatomic, meaning it exists as two oxygen atoms bonded together.

Question 5

What is the reactivity series?

Answer 5

The order of metals from the least reactive to the most reactive.

The reactivity series is a list that ranks metals based on their reactivity.

Question 6

What is a displacement reaction?

Answer 6

When a more reactive metal displaces (replaces) a less reactive metal in a compound.

This type of reaction involves the exchange of elements between compounds.

Question 7

What is the pH of acids?

Answer 7

1-6

Acids have a pH value ranging from 1 to 6, with lower values indicating stronger acids.

Question 8

What is the pH of a neutral solution?

Answer 8

7

A pH of 7 indicates a neutral solution, such as pure water.

Question 9

What is the pH of alkalis?

Answer 9

8-14

Alkalis have a pH value ranging from 8 to 14, with higher values indicating stronger bases.

Question 10

What colours do acids turn in indicators?

Answer 10

• Universal indicator: red
• Phenolphthalein: colourless
• Methyl orange: red
• Litmus: red

Acids typically exhibit specific colour changes in various pH indicators.

Question 11

What colours do alkalis turn in indicators?

Answer 11

• Universal indicator: purple
• Phenolphthalein: pink
• Methyl orange: yellow
• Litmus: blue

Alkalis display distinct colour changes in different pH indicators.

Question 12

What type of salts does Hydrochloric acid produce?

Answer 12

Chloride salts

Hydrochloric acid reacts to form salts known as chlorides.

Question 13

What type of salts does sulphuric acid produce?

Answer 13

Sulfate salts

Sulphuric acid generates salts called sulfates upon reaction.

Question 14

What type of salts does nitric acid produce?

Answer 14

Nitrate salts

Nitric acid forms salts known as nitrates.

Question 15

What is the test for Hydrogen?

Answer 15

A lit splint placed at the neck of a test tube of hydrogen will cause the hydrogen to pop.

This is a classic test for the presence of hydrogen gas.

Question 16

What is the general equation for acids reacting with metals?

Answer 16

Acid + metal → salt + hydrogen

This equation describes the products formed when acids react with metals.

Question 17

What is the general equation for neutralisation?

Answer 17

Acid + alkali → salt + water

Neutralisation reactions typically yield salt and water.

Question 18

What are ions?

Answer 18

Charged particles. Acids contain hydrogen ions and alkalis contain hydroxide ions.

Ions are atoms or molecules that have gained or lost one or more electrons, resulting in a net charge.

Question 19

What does a neutralisation reaction produce?

Answer 19

Two neutral products: salt and water.

Neutralisation reactions balance the acidity and alkalinity, resulting in neutral substances.