Chapters 1 - 10

Question 1

What is conversation of mass?

Answer 1

The total mass remains constant in a chemical reaction

Question 2

What is constant (definite) composition?

Answer 2

All samples of a given compound consist of the same mass fraction

Question 3

What is multiple proportions?

Answer 3

In different compounds of same elements the masses of the combining elements can be expressed in simple ratios

Question 4

What is an example of multiple proportions?

Answer 4

• Carbon monoxide (CO)
• Carbon dioxide (CO2)

Question 5

What did Milkan discover?

Answer 5

He calculated the mass of an electron to be 9.109x10^-31kg based on Thompsons value for the mass/ charge ratio of the electron

Question 6

What is the plum pudding model?

Answer 6

Describes the atom as a blob of positive charge with tiny negative particles embedded in it

Question 7

How was the plum pudding model disproved?

Answer 7

Rutherford’s alpha scattering experiment

Question 8

How was the charge of the electron discovered?

Answer 8

Observations from the oil drop experiment

Question 9

What did Thompson discover in the cathode ray experiment ?

Answer 9

The existence of negatively charged particles

Question 10

Define elements

Answer 10

Simplest type of matter with unique physical and chemical properties consists of atoms

Question 11

Define compounds

Answer 11

Consists of two or more elements that are bonded chemically

Question 12

In atomic notation, what does X represent?

Answer 12

Atomic symbol

Question 13

In atomic notation, what does A represent?

Answer 13

Mass number
- Protons and neutrons

Question 14

In atomic notation, what does Z represent?

Answer 14

Atomic number
- Protons

Question 15

Define isotopes

Answer 15

Same number of protons, different number of neutrons
- Different atomic mass