APES Chapter 2

Matter

Anything that has mass and takes up space

Examples of matter

rocks, water air, books

Mass

A measure of the amount of matter in an object

Weight

the force that results from the action of gravity on mass

Atom

The smallest particle that can contain the chemical properties of an element

Basic building blocks of matter

atoms

-all matter is composed of tiny particles that cannot be broken down into smaller pieces

Element

a substance composed of atoms that cannot be broken down into smaller, simpler components

Examples of elements

gold (solid), mercury (liquid), helium (gas)

How many elements have been produced in laboratories?

24

periodic table

A chart of all chemical elements currently known, organized by their properties

Molecule

a particle that contains more than one atom

Compounds

molecules that contain more than one element

ex: CO2

atomic number

the number of protons in the nucleus of an atom of an element

Neutrons

no electrical charge

Why are neutrons needed in the nucleus?

Are critical to the stability of the nuclei because they keep the positively charged protons together without them protons would repel one another and seperate.

What weights more neutrons or protons?

Protons and neutrons have roughly the same mass

Electrons

negative charge, smaller mass than protons and neutrons

How do electrons get binded to the nucleus?

Opposites attract negatively charged electrons are attracted to positively charged protons.

mass number

the total number of protons and neutrons in a nucleus.

Why is the mass of electrons not included when calculating the mass of an atom?

Insignificant compared with the mass of a proton or neutron

Isotopes

Atoms of the same element that have different numbers of neutrons

radioactive decay

The breakdown of a radioactive element, releasing particles and energy

Parent

original atom

Daughter

resulting decay product

radioactive isotope

unstable isotope

half-life

The time that it takes for one half of an original radioactive parent to decay

Why is the knowledge of half life important?

Allows scientists to determine the length to time that a particular radioactive element may be dangerous.

3 types of chemical bonds

covalent, ionic, hydrogen

covalent bond

A chemical bond formed when two atoms share electrons

ionic bond

Formed when one or more electrons are transferred from one atom to another, opposite charges attract, atom loses an electron become positively charged and other becomes electron rich (negatively charged)

weakest chemical bond

hydrogen bond

strongest chemical bond

covalent

hydrogen bond

a weak chemical bond that forms when hydrogen atoms that are covalently bonded to one atom are attracted to another atom on another molecule

polar molecule

a molecule in which one side of the molecule is slightly negative and the opposite side is slightly positive

Why is water a vital component of most environmental systems?

The molecular structure of water gives it unique properties that support the conditions necessary for life on Earth.

ex: air pollution, water pollution, photosynthesis

-often the vehicle for transferring chemical elements and compound from one system to another.

Cohesion

hydrogen bonding makes water molecules stick strongly to one another

Adhesion

Hydrogen bonding makes water molecules stick to certain other substances.

surface tension

a property of water that results from the cohesion of water molecules at the surface of a body of water and that creates a sort of skin on the water's surface

capillary action

a property of water that occurs when adhesion of water molecules to a surface is stronger than cohesion between the molecules

Water boiling point

212 F and 100 C

Water freezing point

0 C and 32 F

Why is ice being less dense important for living things?

Lakes and bottoms would freeze from the bottom up and as a result very few aquatic organisms would be able to survive in temperate cold climates.

water maximum density

4 degrees C or 39 degrees F as it cools from 4 degrees C its molecules realign into a crystal lattice structure and its volume expands

Acid

any compound that forms H+ ions in solution

Base

a compound that produces hydroxide ions in solution

What happens when acid is dissolved in water?

Dissociates into positively charged hydrogen ions and negatively charged ions

What happens when bases are dissolved in water?

dissociates into negatively charged ions and positively charged ions

pH

The number that indicates the relative strength of acids and bases in a substance

The lower the number the stronger the acid the higher the number the more

basic

ocean acidification

an increase in the acidity of the oceans

Why has atmosphere concentrations of CO2 increased?

Human activity

How has increase in CO2 in the atmosphere has had an important influence on the pH of ocean water?

As atmospheric concentrations of CO2 have increased more atmospheric CO2 has dissolved into the oceans and the oceans become more acidic.

Chemical reaction

a reaction that occurs when atoms separate from molecules or recombine with other molecules

Law of Conservation of Matter

A law of nature stating that matter cannot be created or destroyed; it can only change form ex: paper burning

-tells us why we cannot easily dispose of materials

inorganic compounds

A compound that does not contain the element carbon or contains carbon bound to elements other than hydrogen.

organic compounds

compounds that have carbon-carbon and carbon-hydrogen bonds

biological molecules

carbohydrates, lipids, proteins, nucleic acids

Carbohydrates (Monosaccharides)

A compound composed of carbon, hydrogen, and oxygen atoms in a 1:2:1 ratio

ex: glucose C6H12O6

Types of Carbohydrates

sugars and starches

function of carbohydrates

provides energy, energy storage (not as energy dense)

Proteins (amino acids)

A critical component of living organisms made up in a long chain of nitrogen-containing organic molecules know as amino acids.

-C,H,O,N,S

function of proteins

Structural support, energy storage, internal transport defense against foreign substances

ex: enzymes, antibodies

Enzymes

proteins that help control the rates of chemical reactions

Antibodies

protects us from infections

Nucleic Acid (Nucleotide)

organic compounds found in all living cells

-C,H,O,N,P

types of nucleic acids

DNA and RNA

DNA

the genetic material that carries the code about an organism and is passed from parent to offspring

function of nucleic acids

stores genetic material

RNA

translates the code stored in the DNA and allows for the synthesis of proteins

Lipids (fatty acids)

A smaller organic biological that does not mix with water

-C,H and a few oxygen

types of lipids

fats, oils, waxes, steroids

Cell

a highly organized living entity that consists of the four types of macromolecules and other substances in a watery solution, surrounded by a membrane

Functions of lipids

cell membranes, energy storage

Unicellular

A single celled organism

ex: bacteria, green algae, amoeba

Multicellular

multiple celled organism

ex: humans, brine shrimp, maple tree

Energy

the ability to do work or transfer heat

Joule

the amount of energy used when a 1 watt electrical device is turned on for 1 second.

Power

the rate at which work is done

-energy = power x time

-power= energy/time

kilowatt (kW)

a unit of power

kilowatt-hour (kWh)

unit of energy

-electrical bill reports energy use

electromagnetic radiation

A form of energy emitted by the Sun that includes, but is not limited to, visible light, ultraviolet light, and infrared energy, which we perceive as heat.

Photon

massless packet of energy that carries electromagnetic radiation at the speed of light

What does the amount of energy in a photon depend on?

Wavelength

The shorter the wavelength, the ________ the energy

higher

The longer the wavelength the

lower energy