Nature of Matter

Question 1

What is a substance?

Answer 1

A form of matter that has a fixed composition.

Question 2

What are the classes of substances?

Answer 2

Elements, Mixtures and Compounds

Question 3

What are the characteristics of pure substances?

Answer 3

• Fixed composition
• Cannot be broken down into smaller components by physical methods
• Can only be changed in properties and identity by chemical methods
• Properties do not vary

Question 4

What are the characteristics of a mixture?

Answer 4

• Variable composition
• Constituents retain individual properties
• Separable by physical methods.
• Mixtures of different compositions may have widely different properties.

Question 5

What are the types of mixtures?

Answer 5

• Homogeneous

- Heterogeneous

Question 6

What type of mixture look the same throughout?

Answer 6

Homogeneous mixtures

Question 7

What is the reaction of homogeneous mixtures to light?

Answer 7

It may or may not scatter light.

Question 8

The components of homogeneous mixtures are…

Answer 8

…indistinguishable

Question 9

What are the features of heterogeneous mixtures?

Answer 9

• Composition is not the same throughout

- Components are distinguishable

Question 10

What are the states of matter?

Answer 10

• Solid
• Liquid
• Gas
• Plasma

Question 11

What is the critical temperature of a gas?

Answer 11

It is the temperature below which a gas cannot be liquefied.

Question 12

What property is peculiar to liquids?

Answer 12

They do not have a fixed shape but they have a fixed volume.

Question 13

What is physical change?

Answer 13

It occurs when a substances changes state without a change in its chemical properties. Its physical appearance may change but its chemical properties remain the same.

Question 14

What properties can be affected by physical change?

Answer 14

Colour, Solubility, Density, Texture, Adsorption, Vapor pressure

Question 15

What properties cannot be affected by physical change?

Answer 15

Melting point, Boiling point, Chemical composition

Question 16

What are intensive properties?

Answer 16

These are properties that do not depend on the size/quantity of the matter being considered.

Question 17

What are the examples of intensive properties?

Answer 17

Colour, Boiling Point, Melting Point, Density

Question 18

What are extensive properties?

Answer 18

These properties vary depending on the size/quantity of the matter being considered.

Question 19

What are the examples of extensive properties?

Answer 19

Mass, Volume, Weight, Length,

Question 20

State the law of conservation of matter

Answer 20

It states that matter can neither be created nor destroyed, but it can be converted from one form to another.

OR

There is no observable change in the quantity of matter during a chemical reaction or a physical change.

Question 21

Where can plasma, as a state of matter, be found?

Answer 21

Flames, Lightning, The Sun, etc

Question 22

Who identified the plasmar state of matter?

Answer 22

William Crookes in 1879.

Question 23

Matter is classified based on ___ and ___.

Answer 23

Composition and Properties.

Question 24

What are the classes of matter based on composition?

Answer 24

Element, Compound, Mixture

Question 25

What are the classes of matter based on properties?

Answer 25

Solids, Liquids, Gas, Plasma

Question 26

How can chemical properties be observed?

Answer 26

By using a process that changes the identity of the substance of interest. In other words, it studying the kind of chemical changes it undergoes.

Question 27

What are the properties of plasma?

Answer 27

1. It has no fixed shape or volume. 2. Interionic interaction between charged particles 3. May self-generate electric or magnetic fields.