Chemical Composition

Question 1

What is a compound?

Answer 1

Compounds consist of two or more elements that are chemically combined together.

Question 2

What is an element?

Answer 2

Elements are the basic building blocks of living and non-living matter.

Question 3

What properties do compounds have?

Answer 3

• Compounds do not have the same properties as their constituent elements. (Gas + gas -> liquid)
• The constituent elements of a compound are always chemically combined in a fixed proportion of mass.
• A compound cannot be separated into its constituent elements easily (Water - alot of energy to break down into hydrogen and oxygen)

Question 4

How many properties do compounds have?

Answer 4

3 properties.

Question 5

Name two examples of compounds.

Answer 5

Only 2:
- Water
- Sodium chloride
- Ammonia
- Sodium hydrogencarbonate
- Marble
- Plastic
( Other relevant answers )

Question 6

What are the properties of elements?

Answer 6

• Elements cannot be broken down into simpler substances
• In the periodic table, elements are separated by, [non-metals], [metals], with a zigzag line.
• An element is a material that consists of a single type of atom.
• The diversity of matter we see around us is made up of one and more elements in the periodic table.

Question 7

Name 4 elements.

Answer 7

Check periodic table:

- Oxygen
- Hydrogen
- Calcium
- Chlorine
- Magnesium
- Aluminium
Any other relevant answers

Question 8

Define mixtures.

Answer 8

A mixture is made up of two or more elements and/or compounds that are NOT chemically combined.

Made up of:

• elements only
• compounds only
• both elements and compounds

Question 9

What are the properties of mixtures?

Answer 9

• A mixture has the same characteristics as its constituents.
• Constituents of mixtures do not have a fixed proportion.
• Separation techniques can separate mixtures into its constituents easily.
• A mixture can be separated into its constituents easily.

Question 10

Is a solution a mixture or a compound?

Answer 10

A solution is a mixture.

Question 11

Is a suspension a mixture or a compound?

Answer 11

A suspension is a mixture.

Question 12

What is a solution?

Answer 12

A solution is a mixture in which one substance dissolves completely in another substance.

Question 13

What is a suspension?

Answer 13

A suspension is a mixture that contains insoluble substances in a solvent.

Question 14

What are the characteristics of a suspension?

Answer 14

• If a suspension is left undisturbed, the insoluble substances in a suspension can settle to the bottom or top of the container and form solid deposits.
• Light cannot completely pass through a suspension.
• The insoluble substances in a suspension can be separated by a process called filtration.

Question 15

What is solubility?

Answer 15

• How well a solute dissolves in a fixed volume of a particular solvent.

Question 16

What are the depending factors of solubility?

Answer 16

1. Type of solvent.

2. Type of solute.

Question 17

What are the depending factors of the rate of dissolving?

Answer 17

1. Size of solute particles.
2. Temperature of solvent.
3. Rate of stirring.

The smaller the size of solute particles, the higher the temperature of the solvent, the faster the rate of stirring, the faster the rate of dissolving.