Revision Sheet for Everyday Substances

Question 1

Explain why Carbon is such an important element.

Answer 1

As it has a unique ability to form strong covalent bonds with itself and other elements.

Question 2

Explain what covalent bonding is.

Answer 2

Bonding between two non-metals in which they share electrons

Question 3

What is a hydrocarbon

Answer 3

Molecules made up of only hydrogen and carbon

Question 4

How are hydrocarbons found? Where are they formed?

Answer 4

Hydrocarbons are found in organic compounds such as petrol and diesel among other fossil fuels. They form millions of years underground through the remains of dead organims.

Question 5

Alkenes formula

Answer 5

CnH2n

Question 6

First five alkenes and their chemical formula

Answer 6

Ethene - C2H4
Propene - C3H6
Butene - C4H8
Pentene - C5H10
Hexene - C6H12

Question 7

First ten alkanes and their chemical formula

Answer 7

Methane - CH4
Ethane - C2H6
Propane - C3H8
Butane - C4H10
Pentane - C5H12
Hexane - C6H12
Heptane - C7H16
Octane - C8H18
Nonane - C9H20
Decane - C10H22

Question 8

State the name of three indicators, their pH ranges, and colours

Answer 8

1. Universal indicator, (pH 0-14) (red-purple, explain more….)
2. Methyl Orange (pH 3 - 5), red when acidic, yellow when alkaline
3. Litmus (pH 4 - 9), red when acidic, blue when alkaline

Question 9

Using a diagram explain how a fractionating tower works?

Answer 9

1. Heat the liquid mixture
2. Vapor rises
3. Different components go on different levels due to differing boiling points

Question 10

What is the difference between a saturated and unsaturated hydrocarbon?

Answer 10

Saturated hydrocarbons have only single bonds and unsaturated hydrocarbons have double or triple bonds

Question 11

Write a definition for an acid and a base. Give an example of an acid and a base that would be found in a laboratory.

Answer 11

An acid is a substance that typically has a low pH value and tends to taste sour. It can react with metals to produce hydrogen gas and has the ability to neutralize bases.

Example of an acid in a laboratory: Hydrochloric acid (HCl)

A base is a substance that typically has a high pH value and tends to taste bitter or feel slippery

Example of a base in a laboratory: Sodium hydroxide (NaOH)

Question 12

Explain where acids and bases can be found in everyday life and the general jobs they perform?

Answer 12

Acids
1. Household cleaning products
2. Food and beverage
3. Car batteries
4. Industrial processes
Bases
1. Cleaning products
2. Personal care products
3. Agriculture

Question 13

Explain what an indicator is and how they work

Answer 13

An indicator is a substance that changes color or exhibits a visible change when it comes into contact with an acid or a base. It helps in determining the pH of a solution or identifying whether a substance is acidic or basic.

Question 14

Write a general reaction of the reaction of an acid with: a. base -

b. a metal

c. carbonate -

Answer 14

a. Metal salt + acid
b. Metal salt + hydrogen
c. Metal salt + water + carbon dioxide