Ch 2 Quiz A&P

Matter

The "stuff" of the universe.

States of matter

Solid - has definite shape and volume.

Energy

The capacity to do work (put matter into motion).

Types of energy

Kinetic - energy in action.

Forms of Energy

Chemical - stored in the bonds of chemical substances.

Energy Form Conversions

Energy is easily converted from one form to another.

Energy Questions

What form of energy is found in the food we eat?

Elements

Unique substances that cannot be broken down by ordinary chemical means.

Atoms

More-or-less identical building blocks for each element.

Atomic symbol

One- or two-letter chemical shorthand for each element.

Physical properties

Those detected with our senses.

Chemical properties

Pertains to the way atoms interact with one another.

Major Elements of the Human Body

Oxygen (O), Carbon (C), Hydrogen (H), Nitrogen (N).

Lesser elements

Make up 3.9% of the body and include Calcium (Ca), phosphorus (P), potassium (K), sulfur (S), sodium (Na), chlorine (Cl), magnesium (Mg), iodine (I), and iron (Fe).

Trace elements

Make up less than 0.01% of the body and are required in minute amounts, found as part of enzymes.

Nucleus

Consists of neutrons and protons.

Neutrons

Have no charge and a mass of one atomic mass unit (amu).

Protons

Have a positive charge and a mass of 1 amu.

Electrons

Found orbiting the nucleus, have a negative charge and 1/2000 the mass of a proton (0 amu).

Planetary Model

Electrons move around the nucleus in fixed, circular orbits.

Orbital Model

Regions around the nucleus in which electrons are most likely to be found.

Atomic number

Equal to the number of protons.

Mass number

Equal to the mass of the protons and neutrons.

Atomic weight

Average of the mass numbers of all isotopes.

Atomic number for H

1

Atomic number for He

2

Atomic number for Li

3

Mass number for H

1

Mass number for Ne

20

Mass number for Li

7

Isotope

Atoms with the same number of protons but a different number of neutrons.

Radioisotopes

Atoms that undergo spontaneous decay called radioactivity.

Molecule

Two or more atoms held together by chemical bonds.

Compound

Two or more different kinds of atoms chemically bonded together.

Mixtures

No chemical bonding takes place; can be separated by physical means.

Heterogeneous Mixture

A mixture that is not uniform in composition.

Homogeneous Mixture

A mixture that is uniform in composition.

Chemical Bond

An attraction between atoms that allows the formation of chemical substances.

Electron Shells

Energy levels that surround the nucleus of an atom.

Valence Shell

The outermost energy level containing chemically active electrons.

Octet Rule

Atoms interact to have eight electrons in their valence shell, except for the first shell which is full with two electrons.

Chemically Inert Elements

Elements that have their outermost energy level fully occupied by electrons.

Chemically Reactive Elements

Elements that do not have their outermost energy level fully occupied by electrons.

Ionic Bonds

Bonds formed between atoms by the transfer of one or more electrons.

Ions

Charged atoms resulting from the gain or loss of electrons.

Anions

Ions that have gained one or more electrons, developing a negative charge.

Cations

Ions that have lost one or more electrons, developing a positive charge.

Ionic Compounds

Compounds that form crystals instead of individual molecules.

Example of Ionic Compound

NaCl (sodium chloride).

Ionic Compound Example 1

MgCl2.

Ionic Compound Example 2

CaCl2.

Ionic Compound Example 3

KCl.

Covalent bonds

Covalent bonds are formed by the sharing of two or more electrons.

Electron sharing

Electron sharing produces molecules.

Single Covalent Bonds

A type of covalent bond where two atoms share one pair of electrons.

Double Covalent Bonds

A type of covalent bond where two atoms share two pairs of electrons.

Triple Covalent Bonds

A type of covalent bond where two atoms share three pairs of electrons.

Covalent Compounds

Examples include CH4, H2O, CO2, NH3, and O2.

Nonpolar molecules

Electrons shared equally between atoms produce nonpolar molecules.

Polar molecules

Unequal sharing of electrons produces polar molecules.

Electronegative atoms

Atoms with six or seven valence shell electrons are electronegative.

Electropositive atoms

Atoms with one or two valence shell electrons are electropositive.

Hydrogen Bonds

Too weak to bind atoms together

Chemical Reactions

Occur when chemical bonds are formed, rearranged, or broken

Chemical Equations

Written in symbolic form using chemical equations

Combination Reactions

Synthesis reactions which always involve bond formation

Decomposition Reactions

Molecules are broken down into smaller molecules

Exchange Reactions

Bonds are both made and broken

Oxidation-Reduction (Redox) Reactions

Reactants losing electrons are electron donors and are oxidized

Exergonic Reactions

Reactions that release energy

Endergonic Reactions

Reactions whose products contain more potential energy than did its reactants

Reversibility in Chemical Reactions

All chemical reactions are theoretically reversible

Factors Influencing Rate of Chemical Reactions

Temperature - chemical reactions proceed quicker at higher temperatures

Catalysts

Increase the rate of a reaction without being chemically changed

Enzymes

Biological catalysts

Biochemistry

Organic compounds contain carbon, are covalently bonded, and are often large

Inorganic Compounds

Do not contain carbon

Properties of Water

High heat capacity - absorbs and releases large amounts of heat before changing temperature

Salts

Inorganic compounds containing cations other than H+ and anions other than OH-

Acids

Release H+ and are therefore proton donors

Bases

Release OH- and are proton acceptors

Acidic Solutions

Have higher H+ concentration and therefore a lower pH

Alkaline Solutions

Have lower H+ concentration and therefore a higher pH

Neutral Solutions

Have equal H+ and OH- concentrations

Buffers

Systems that resist abrupt and large swings in the pH of body fluids

Carbonic Acid-Bicarbonate System

Carbonic acid dissociates, reversibly releasing bicarbonate ions and protons

Chemical Equilibrium

The chemical equilibrium between carbonic acid and bicarbonate resists pH changes in the blood