Chemistry Test (Revision)

Question 1

What is chemistry?

Answer 1

The study of matter and its composition, it seeks to expand the understanding of matter and its properties. (Energy is a property of matter)

Question 2

Characteristics of matter:

Answer 2

• Made up of particles (atoms, molecules, or ions)
• Particles are in constant motion
• Has a mass
• Occupies a volume in space

Question 3

What is matter?

Answer 3

Any substance that occupies a space and has a mass.

Question 4

What is a pure substance?

Answer 4

A pure substance has a definite and uniform chemical composition.

Question 5

What is an element?

Answer 5

A substance composed from one atom.

Question 6

What is a compound?

Answer 6

Is composed from two or more kinds of atoms in a fixed ratio.

Question 7

What is a mixture?

Answer 7

A combination of two or more pure substances that retain (keep) their individual properties.

Question 8

What is a homogenous mixture?

Answer 8

Has uniform composition and properties throughout.

Question 9

What is a heterogenous mixture?

Answer 9

Has a non-uniform composition and varying properties

Question 10

Physical change:

Answer 10

Matter changes form but not chemical identity.

Question 11

Chemical change:

Answer 11

A chemical reaction occurs and new products are formed.

Question 12

What is an electrons’ relative charge?

Answer 12

-1

Question 13

What is a protons’ relative charge?

Answer 13

+1

Question 14

What is a neutrons’ relative charge?

Answer 14

0

Question 15

Location of electron:

Answer 15

Outside nucleus
Electron cloud

Question 16

Location of proton:

Answer 16

Nucleus

Question 17

Location of neutron:

Answer 17

Nucleus

Question 18

What is the relative mass of an electron?

Answer 18

0

Question 19

What is the relative mass of a proton?

Answer 19

1

Question 20

What is the relative mass of a neutron?

Answer 20

1

Question 21

What are isotopes?

Answer 21

Isotopes are the same element with different number of neutrons (same atomic number but different atomic mass).

Question 22

What is a relative mass?

Answer 22

The weighted average of all the isotopes of an element.

Question 23

What are valence electrons?

Answer 23

Valence electrons are the electrons in the outermost shell or energy level of an atom (the remaining electrons are known as core electrons).

Question 24

What is simple distillation used to separate?

Answer 24

A solvent from solution (sugar/salt and water for example)

Question 25

What is fractional distillation used to separate?

Answer 25

Used to separate a mixture of all liquids (alcohol and water for example)

Question 26

What is filtration used to separate?

Answer 26

Solids from liquids using filter paper (sand and water for example)

Question 27

What is crystallization used to separate?

Answer 27

A solid from its liquid solution in the form of pure crystals (sugar/salt in water for example)

Question 28

What is chromatography used to separate?

Answer 28

Mixtures of soluble substances that are often colored