Unit 2

Question 1

chemistry

Answer 1

the study of the composition and structure of matter and of the changes that matter undergoes

Question 2

matter

Answer 2

Whatever occupies space and can be percieved by our senses

Question 3

mass

Answer 3

The quantity of matter

The quantity of matter is conserved

Question 4

The Law of Conversion of Mass

Answer 4

No mass is lost from the start of a process to the end

Question 5

extensive property (of matter)

Answer 5

a property that depends on the amount of substance (mass, volume, etc.)

Extensive properties are a physical property of matter

Question 6

intensive property of matter

Answer 6

a property of matter that does not depend on the amount of substance (color, melting point, density)

Intensive properties are physical properties of matter

Question 7

Physical property of matter

Answer 7

Can be observed without doing a chemical reaction (luster, hardness, color)

Question 8

Chemical property of matter

Answer 8

Property that can be observed through chemical reaction (flammability, reactivity, etc)

Question 9

Pure Substance

Answer 9

• Same physical and chemical properties throughout
• Cannot be separated into simpler substances by a physical process

ex. elements, compounds

Question 10

Mixture

Answer 10

• Combination of two or more pure substances
• Can be separated by physical processes

Question 11

Element

Answer 11

A pure substance that cannot be separated into simpler substance by any chemical process

This includes diatomic and polyatomic molecules w only one element

Question 12

Common Diatomic Molecules

Answer 12

Br I N Cl H O F

Question 13

Common Polyatomic Molecules

Answer 13

P and S

Question 14

Compounds

Answer 14

• Pure substance composed of two or more different elements bonded together in fixed proportions (ex. water, carbon dioxide)
• Compounds can be broken down into individual elements via chemical means
• All samples of a particular compound contain the same elements combined in the same proportions (The Law of Constant Composition/Law of Definite Proportions)

The chemical formula denotes the elements and their respective proportions in a given compound. If these proportions change, the compound has changed.

Question 15

The Law of Constant Composition/ The Law of Definite Proportions

Answer 15

All samples of a particular compound contain the same elements combined in the same proportions

Question 16

Homogeneous Mixtures

Answer 16

Components are distributed uniformly through the sample and have no visible boundaries or regions

Ex. sugar in coffee

Question 17

Heterogeneous Mixtures

Answer 17

Components are not distributed uniformly, and there may be distinct regions with different compositions

Ex. sand in water

Question 18

Plasma

Answer 18

A state of matter, superheated matter similar to a gas, but made up entirely of charged particles

Question 19

Lavoisier 1789

Answer 19

• The law of multiple proportions and mass cannot be created/destroyed
• If two elements can form more than one compound together, the ratio of the masses of the second element will always be a whole number when combining with a fixed mass of the first element

Eg. CO and CO2 (same amount of carbon, whole number ratio b/w oxygen and carbon)

Question 20

Dalton 1807

Answer 20

• Atoms are indestructible+ Atomic Theory+ Law of Multiple Proportions

Question 21

Atomic Theory (Dalton 1807)

Answer 21

1. Matter is composed of atoms, the smallest particle capable of participating in chemical reactions
2. Elements contain only one type of atom, characteristic of that particular element
3. Atoms of one element have different properties than atoms of other elements
4. Law of definite proportions
5. Atoms are neither created nor destroyed during a chemical reaction, but are rearranged

Question 22

Mendeleev-1869

Answer 22

Arranged the elements to form the Periodic Table of Elements

Question 23

Goldstein 1885

Answer 23

• Discovered positive particles

Question 24

Thomson 1897

Answer 24

Discovered the electron using cathode rays, developed the plum pudding model

Question 25

Rutherford 1907

Answer 25

* Gold foil experiment * Alpha particles used to bombard gold foil, mass discovered at the center of the atom * The atom itself is mostly empty space

Question 26

Milikan-1909

Answer 26

Determined the mass and charge of an electron with the oil drop experiment

Question 27

Bohr 1913

Answer 27

Electrons orbiting in shells around the nucleus, can be excited and move to higher energy orbitals

Question 28

Heisenberg 1925

Answer 28

Uncertainty principle: You cannot know the energy and location of an electron at the same time

Question 29

Chadwick-1932

Answer 29

Discovered the neutron, necessary to balance the positive nucleus

Question 30

Atomic Mass Units (amu)

Answer 30

* unit used to express the relative masses of atoms and subatomic particles * Carbon 12= 12 amu (6 protons + 6 neutrons) * 1 amu =1 dalton (Da)

Question 31

The Modern Periodic Table Periods

Answer 31

* Period 1: Alkali Metals * Period 2: Alkaline Earth Metals * Period 17: Halogens * Period 18: Noble Gases

Question 32

Metals Characteristics

Answer 32

* Shiny solids (besides Hg) * Conduct heat and electricity * Are malleable

Question 33

Nonmetals characteristics

Answer 33

* Solids, liquids, and gases * Nonconductors * The solids are brittle

Question 34

Metalloids

Answer 34

* shiny solids (like metals) * brittle (like nonmetals) * semiconductors

Question 35

Aston-1919

Answer 35

* Aston developed a mass spectrometer, which showed through experimentation that two different masses of neon gas exist

Question 36

Ions

Answer 36

* Neutral atoms that gain/lose electrons become ions * Ions are held together by electrostatic force (opposites attract)

Question 37

Cation vs. anion

Answer 37

* Cations have a positive charge (less electrons than normal) * Anions have a negative charge (more electrons than normal)

Question 38

Ionic Compounds

Answer 38

* Made from a metal and a nonmetal * Metals form cations; nonmetals form anions * Charges depend on periodic table location

Question 39

formula unit

Answer 39

the smallest electrically neutral unit of an ionic compound

Question 40

Molecular compounds

Answer 40

Composed of atoms held together in molecules by covalent bonds and are composed of nonmetals

Question 41

Covalent bonds

Answer 41

Bond between two atoms created by sharing one or more pairs of electrons

Question 42

Molecular formula

Answer 42

Shows the number and type of atoms present in one molecule of a compound

Question 43

Empirical formula

Answer 43

Shows the smallest whole-number ratio of elements in a compound