Chapter 3

Question 1

discovered oxygen, observed that plants released oxygen into the air (photosynthesis)

Answer 1

Joseph Priestley

Question 2

discovered the role oxygen plays in combustion. He recognized and named oxygen

Answer 2

Antoine Lavoisier

Question 3

year in which the Law of Conservation of Mass was formulated

Answer 3

1774

Question 4

Law of Conservation of Mass

Answer 4

states that for any system closed to all transfers of matter and energy, the mass of the system must remain constant over time, as system’s mass cannot change, so quantity cannot be added nor removed

Question 5

Law of Definite Proportions

Answer 5

states that a given chemical compound always contains its component elements in fixed ratio and does not depend on its source and method of preparation.

Question 6

Matter is made up of extremely small invisible particles called atoms

Answer 6

Dalton’s atomic theory

Question 7

Isotopes

Answer 7

variants of a particular chemical which differ in neutron number, and consequently in neutron number.