Impact of Chemistry - Rutgers NB, Chemistry Final Exam

Matter

Tangible material that makes up everything in the universe

Atom

The smallest unit of matter that cannot be broken down (except in nuclear reactions)

Scientific Method

The general approach used for scientific experimentation worldwide

Steps of Scientific Method

1. Observation

2. Hypothesis

3. Experiments

4. Data Collection

5. Theory

Hypothesis

An initial best guess about your observation that can be tested by experiment

Theory

Detailed explanation of the experimental results. Cannot be proved

Dimensional Analysis

A method that uses conversion factors to convert from one unit to another

Atoms

3 Types of Particles : positive, negative and neutral

The number of pos. particles equal number of neg. particles

Atom Structure

- Dense positively charged nucleus (location of pos. protons and neutral neutrons)

- Cloud-like smear of negative charge around nucleus (location negatively charged electrons)

Atomic Number

Is equal to the number of protons an atom has

Periods

Horizontal rows in periodic table

Groups/Families

Vertical columns in periodic table

Protons + Neutrons =

Mass number (superscript number)

Isotopes

Atoms that have the same number of electrons, the same number of protons, but different numbers of neutrons

Mass Number - Number of Protons =

Neutrons

Uses for Isotopic Percentages

Carbon Dating, Forensic Analysis, Identification of the Origin of a Sample of Matter

Number of Electrons =

Number of Protons

Ground State

Lowest energy level of a particular electron

Excited State

When an electron is energized, moves to a higher energy level

Radiant Energy

Energy given off in the form of light when electrons relax and return to a lower energy level (Depends on the difference between energy levels)

Electromagnetic Spectrum

Different types of light on the scale

Wavelength

How light is classified; distance from one peak to the next of a wave; the shorter the more energetic

Line Spectrum

Pattern of lines of light that is characteristic of a given element; Specific wavelengths, given of by a specific element, of light that correspond to the spacing between energy levels of atoms

Periodic Table Parts

Metals, Nonmetals, Metalloids

Metals

Mostly shiny solids; malleable, ductile, conduct electricity

Nonmetals

Mostly solids and gases; brittle, not malleable or ductile, do not conduct electricity

Metalloids

Found in semiconductors - these materials conduct electricity in certain conditions

Organic Substances

Carbon based

Inorganic

Not carbon based

Pure Substance

A specimen of matter that contains only a single element or compound

Mixture

Defined as one or more pure substances combined together

Heterogeneous Mixtures

Mixtures with boundaries we can see

Homogeneous Mixtures

Mixtures that are uniform in appearance

Pure Substance - Element

Contains atoms from only one element

Pure Substance - Compound

Contains atoms from more than one element

Law of Constant Composition

A given compound has a fixed and definite number of atoms of its constituent elements

Lone Pair

A pair of electrons in a Lewis Dot Structure, also called nonbonding pair

Ionic Bond

Exists between metal and nonmetal

Covalent Bonding

Exists between two or more nonmetals

Ion

Electrically charged atom

Cation

Positively charged ions

Anion

Negatively Charged ions

Covalent Bonds

Occur when electrons are shared between two atoms

Diatomic Molecule

A covalent bond between atoms of the same element

Nonpolar Covalent Bond

Bond between atoms of the same element; no lopsidedness in electron sharing

Polar Covalent Bonds

An unequal sharing of electrons in the bond

Bond Polarity (Most polar to least)

1. Ionic Bonds

2. Polar Covalent Bonds

3. Nonpolar Covalent Bonds

Metallic Bonds

Bonds within a pure chunk of metal; form a sea of negative charge - electrons move through the whole lattice of cations

Determining Electronegativity

Large: ionic bond

Moderate: polar covalent bond

Negligible: nonpolar covalent bond

Sources of Carbon on Earth

1. Atmosphere, in the form of carbon dioxide (400 p p m), methane (1.8 p p m), and carbon monoxide (trace amounts).

2. Carbonate-containing rocks, fossil fuels, and soils.

3. Plants and animals, where carbon atoms are combined with hydrogen, oxygen, and nitrogen.

4. Dissolved in surface and ocean water.

Ions

positively and negatively charged atoms

ionic compound

A compound that consists of positive and negative ions

Ion Charges of Metals and Non-Metals

Elements from Groups 1 and 2 form cations with +1 and +2 charges

Elements from Groups 16 and 17 form anions with −2 and −1 charges

naming ionic compounds

metal (positive ion) comes first, then negative ion (one syllable + ide)

polyatomic ion

an ion made of two or more atoms

Common Polyatomic Ions

○ NO3- Nitrate

○ OH- Hydroxide

○ SO42- sulfate

○ CO32- carbonate

○ PO43- phosphate

○ NH4+ ammonia

○ HCO3- hydrogen carbonate

mole

as the number of carbon atoms in exactly 12 g of pure carbon-12.

Avogadro's number

number of representative particles in a mole, 6.02 X 10^23

molar mass

adding up the atomic masses for the different types of atoms

greenhouse gases

Gases such as carbon dioxide, methane, nitrous oxide, water vapor, and ozone in the atmosphere which are involved in the greenhouse effect.

molecular shape

The geometric shape formed by atoms bonded to the central atom in a molecule

lone pair

a pair of electrons that is not involved in bonding and that belongs exclusively to one atom

Electronegativity

the ability of an atom to attract electrons when the atom is in a compound

Increases from left to right on periodic table

Learning from the past

Co2 is rising since 1958

Since 1800s, CO2 and other greenhouse gases accumulated in the atmosphere

weather and climate

weather is "now" and climate is the average weather over a period of time

fossil fuels

Coal, oil, natural gas, and other fuels that are ancient remains of plants and animals.

Composition of water

Water is a liquid at standard temperature and pressure (S T P): 25°C and 1 atm

Water has an anomalously high boiling point (100°C)

When water freezes, it expands

polar covalent bond

A difference in the electronegativity of the atoms in a covalent bond

non polar covalent bond

a covalent bond in which the bonding electrons are shared equally by the bonded atoms, resulting in a balanced distribution of electrical charge

hyrdrogen bond

electrostatic attraction between a hydrogen atom bonded directly to an atom of N, O, or F and an atom of N, O, or F

1. Hydrogen atom...

2. ...bonded to a N, O, or F.

3. N, O, or F in another molecule (could be the same type of molecule).

specific heat

(1.00 cal/g°C) - a lot of energy required to change the temperature; moist air stores heat energy

Solution

A homogeneous mixture of two or more substances

made up of solvents and solutes.

Concentrations of Solutions

expressed as the number of moles of solute in the solution per Liters of the total solution

Molarity

moles of solute/liters of solution

Ionic Compounds/Solubility

Group 1 Metals, NH4+ - none

Nitrates - none

Chlorides - silver, mercury(I), lead(II)

Sulfates - strontium, barium, lead(II), silver(I)

Carbonates - Group 1 metals, N H4+

Hydroxides, Sulfides - Group 1 metals, N H4+

strong electrolyte

If a compound completely dissociates into ions in water

weak electrolyte

if a compound partially dissociates into ions in water

nonelectrolyte

If a compound dissolves in water, but does not dissociate into ions

like dissolves like

polar and ionic solutes will dissolve in polar solvents, nonpolar solutes will dissolve in nonpolar solvents

Acids and Bases

neutralize each other

neutralization reaction

a chemical reaction in which an acid and a base interact with the formation of a salt

pH scale

scale with values from 0 to 14, used to measure the concentration of H+ ions in a solution; a pH of 0 to 7 is acidic, a pH of 7 is neutral, and a pH of 7 to 14 is basic

Lower the pH the more acidic it is

ocean acidification

decreasing pH of ocean waters due to absorption of excess atmospheric CO2 from the burning of fossil fuels

acid rain

Rain containing acids that form in the atmosphere when industrial gas emissions (especially sulfur dioxide and nitrogen oxides) combine with water.

fuels

Substances burned as a source of heat and power, such as coal, wood, or oil.

Glucose

the form of sugar that circulates in the blood and provides the major source of energy for body tissues. When its level is low, we feel hunger.

Combustion

There are three requirements to generate a fire: a source of heat, a fuel, and an oxidizer

Fuel + Oxidizer ---> Heat = Products

Hyrdocarbons

organic molecules consisting of only carbon and hydrogen

Energy

the ability to do work

potential energy

Energy that is stored and held in readiness

kinetic energy

energy due to motion

work

force x distance

Law of Thermodynamics

energy cannot be created or destroyed, only transformed

Temperature

A measure of how hot or cold something is.

Units of energy

Joules (J) and calories (cal)

calometer

Device to measure the heat transferred in a reaction

exothermic reaction

a chemical reaction in which heat is released to the surroundings

endothermic reaction

A reaction that ABSORBS energy in the form of heat

bond energy

the amount of energy that will break a bond between two atoms