Chapter 1

Question 1

Matter

Answer 1

anything that occupies space and has mass.

Question 2

Atoms

Answer 2

the basic particles that compose ordinary matter

Question 3

molecules

Answer 3

Atoms often bound together in specific geometrical arrangements

Question 4

Structure of molecules

Answer 4

Determines properties of molecule

Question 5

substance

Answer 5

A specific instance of matter—such as air, water, or sand

Question 6

state

Answer 6

The first classification of matter

Question 7

Composition

Answer 7

The second classification of matter

Question 8

A pure substance

Answer 8

made up of only one type of particle (one component), and its composition is invariant (it does not vary from one sample to another)

Question 9

A mixture

Answer 9

a substance composed of two or more particles in proportions that can vary from one sample to another

Question 10

element

Answer 10

a substance that cannot be chemically broken down into simpler substances.

Question 11

compound

Answer 11

substance composed of two or more elements (in this case hydrogen and oxygen) in fixed, definite proportions

Question 12

heterogeneous mixture

Answer 12

one in which the composition varies from one region of the mixture to another—the different particles that compose water and sand do not mix uniformly.

Question 13

homogeneous mixture

Answer 13

one with the same composition throughout—the particles that compose sweetened tea mix uniformly.

Question 14

hypothesis

Answer 14

a tentative interpretation or explanation of the observations

Question 15

scientific law

Answer 15

a series of similar observations

Question 16

law of conservation of mass

Answer 16

Matter is neither created nor destroyed

Question 17

theory

Answer 17

One or more well-established hypotheses

Question 18

Law of Conservation of Mass

Answer 18

In a chemical reaction, matter is neither created nor destroyed.

Question 19

chemical reaction

Answer 19

a process in which one or more substances are converted into one or more different substances.

Question 20

law of definite proportions

Answer 20

All samples of a given compound, regardless of their source or how they were prepared, have the same proportions of their constituent elements.

Question 21

Law of Multiple Proportions

Answer 21

When two elements (call them A and B) form two different compounds, the masses of element B that combine with 1 g of element A can be expressed as a ratio of small whole numbers.

Question 22

John Dalton and the Atomic Theory

Answer 22

1) Each element is composed of tiny, indestructible particles called atoms.

2) All atoms of a given element have the same mass and other properties that distinguish them from the atoms of other elements.

3) Atoms combine in simple, whole-number ratios to form compounds.

4) Atoms of one element cannot change into atoms of another element. In a chemical reaction, atoms only change the way that they are bound together with other atoms.

Question 23

J. J. Thomson

Answer 23

Used cathode rays to find charge-to-mass ratio of the cathode ray particles by deflecting them using electric and magnetic fields

Question 24

What did J.J Thomson discover

Answer 24

He discovered the electron

Question 25

Robert Millikan

Answer 25

deduced the charge of a single electron

Question 26

What did J.J Thomson propose?

Answer 26

The plum-pudding model: negatively charged electrons were small particles held within a positively charged sphere.

Question 27

radioactivity

Answer 27

he emission of small energetic particles from the core of certain unstable atoms

Question 28

Rutherford’s Gold Foil Experiment

Answer 28

Disproved the plum-pudding model and proposed the nuclear theory.

Question 29

Nuclear theory

Answer 29

1) Most of the atom’s mass and all of its positive charge are contained in a small core called the nucleus.

2) Most of the volume of the atom is empty space, throughout which tiny, negatively charged electrons are dispersed.

3) There are as many negatively charged electrons outside the nucleus as there are positively charged particles (named protons) within the nucleus, so that the atom is electrically neutral.

Question 30

James Chadwick

Answer 30

demonstrated that the previously unaccounted for mass of atom was due to neutrons

Question 31

atomic number

Answer 31

The number of protons in an atom’s nucleus and is given the symbol Z

Question 32

Isotopes

Answer 32

When the Number of Neutrons Varies

Question 33

natural abundance

Answer 33

The abundance of isotopes of a chemical element as naturally found on a planet

Question 34

mass number

Answer 34

The sum of the number of neutrons and protons in an atom and is represented by the symbol A:

Question 35

Ions

Answer 35

Losing and Gaining Electrons

Question 36

Atomic mass

Answer 36

the mass of an atom of a chemical element expressed in atomic mass units

Question 37

mass spectrometry

Answer 37

a technique that separates particles according to their mass.