CHM 144 Exam I

Scientific Laws

“The What” Observable and reproducible predictions of the natural world

Scientific Theories

“The Why” Explanations for why natural phenomena occur

Scientific Models

Representations of objects, systems, or events that are used as tools for understanding the natural world

Chemistry

The study of the properties and behavior of matter

Matter

Physical material of the universe

Properties

Distinguishable characteristics of matter

Elements

Substances are the simplest types of matter with unique chemical and physical properties

Atom

Matter spheres that are under a billionth of a meter across

Molecule

An independent structure consisting of two or more atoms

Compounds

An independent structure composed of two or more different elements that are chemically bound together

Mixture

A group of two or more substances (elements or compounds) that are physically intermingled

Homogenous

Evenly mixed

Heterogenous

Unevenly mixed

Classification of oxygen gas

Molecule of an element

Classification of steel

Homogeneous mixture

Classification of iced coffee

Heterogeneous mixture

Classification of iron metal

Atoms of an element

Classification of carbon dioxide gas

Molecules of a compound

Solids

Definite shape and volume

Liquids

Definite volume, shape, conforms to container

Gases

Both shape and volume conform to container

Physical properties of matter

Properties of matter that may be observed or measured without changing its identity and composition

Chemical properties of matter

Properties of matter’s capacity to change in identity or composition

Intensive Physical Properties

Do not change if you increase/decrease the amount of a substance

Extensive Physical Properties

Changes if you increase/decrease the amount of substance

Measurement

The process of empirical, object assignment of numbers to the properties of objects and events of the real world

Units of Measurement

Standardized quantity of a physical property

SI Units

Default units used in scientific measurements

Kelvin Scale

Devised to accommodate lowest possible temperature the a zero-point

Dimensional Analysis

Analyzing the relationship between different physical quantities and tracking these dimensions as calculations are performed

Density

Mass / Volume

Measurement Error

Random deviations in values measured around an average value

Systematic Error

Consistent deviation (higher or lower) from a true value

exa (E)

10^18

peta (P)

10^15

tera (T)

10^12

giga (G)

10^9

mega (M)

10^6

kilo (k)

10³

hecto (h)

10²

deka (da)

10^1

deci (d)

10^-1

centi (c)

10^-2

milli (m)

10^-3

micro (u)

10^-6

nano (n)

10^-9

pico (p)

10^-12

fento (f)

10^-15

Dalton’s Atomic Theory - Law of Multiple Propportions

Compounds are composed of more than one element

Dalton’s Atomic Theory - Law of Conservation of Mass

Chemical reactions only rearrange atoms, no atoms are created or destroyed in chemical reactions

Thompson Cathode Experiment

Particles are negatively charged and were determined to have a charge mass/ratio of -1.76 × 10^8 g/C

Direction of Deflection

Provided charge information

Magnitude of Deflection

Provided mass/charge ratio information

Early Model of the Atom

Positive matter spread through atom and negative electron dot embedded in and on the surface of the atom

Thompson Radiation Experiment

Determined that radiation was made of positively charged particle, negatively charge particles, and neutral radiation

Rutherford Scattering Experiment

Atom must have a small, dense positive core

Sending a cathode ray through an electric field will bend the field toward which electric plate?

Toward the positive plate because the cathode ray is made up of negatively charged particles (electrons)

Sending a ray of alpha particles through an electric field will bend the field toward which electric plate?

Toward the negative plate because the alpha particles are positively charged particles

Electron mass

9.10938×10^-28

Proton mass

1.67262×10^-24

Neutron mass

1.67493×10^-24

Electron charge

-1

Proton charge

+1

Neutron charge

0

Electron symbol

e^-

Proton symbol

p^+

Neutron symbol

n^0

Order of elements on periodic table

Number of protons

Metals

Conduct electricity and heat

Nonmetals

Do not conduct electricity and heat

Metalloids

Have a special set of metal and nonmetal properties

Metal + Nonmetal

Ionic compound

Nonmetal + Nonmetal

Molecular Compound

Periods

Rows on a periodic table

Groups

Columns on a periodic table

Families

Certain columns or blocks on a periodic table that have similar chemical properties

Alkali Metals

Group 1 - hydrogen

Alkaline Earth Metals

Group 2

Transition Metals

Groups 3-11

Chalcogens

Group 16

Halogens

Group 17

Noble Gases

Group 18

Mass Number

Number of protons and neutrons

Atomic Number

Number of protons

Isotopes

Atoms of the same element but different numbers of neutrons

Atomic Weight

Isotope mass x fractional abudance

Ion

An atom or molecules with a net electric charge

Cation

Ion with a positive charge

Anion

Ion with a negative charge

Lithium (Li) charge

+

Sodium (Na) charge

+

Potassium (K) charge

+

Rubidium (Rb) charge

+

Caesium (Cs) charge

+

Magnesium (Mg) charge

2+

Calcium (Ca) charge

2+

Strontium (Sr) charge

2+

Barium (Ba) charge

2+

Vanadium (V) charge

2+ / 3+

Chromium (Cr) charge

2+ / 3+