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anything that occupies space and has mass - composed of chemical elements
A substance that cannot be broken down to other substances by ordinary cemical means.
How many elements are recognized and found in nature
96% of the total amount of essenial chemical to life
Oxygen Carbon Hydrogen and Nitrogen
Most of the remaining 4% of chemicals essential to life are:
Trace elements (minute (less than .01%) quantities required for life)
substance consisting of two or more different elements combined ina fixed ratio
Sugar is formed by what chemicals
Carbon hydrogen and oxygen
what is the chemical compostition of table salt
sodium chloride, NaCl
smallest unit of matter that still retains the properties of an element.
- subatomic particle wiith a single positive Electrical charge
- subatomic particle with a single Negatice electrical charge
electrically neutral particle ( no charge )
What particles are found in the nucleus
neutrons and protons
The number of protons in each atom of a particular element.
Unless otherwise indicated, an atom has an equal number of protons and ___ and thus its net electrical charge is zero
sum of the protons and neutrons in its nucleus
Mass of a proton and the mass of a neutron are almost identical and are expressed in a unit of measurement called ___
Electron has ____ the mass of a proton
The approximate total mass of an atom;also called atomic weight. Given as a whole number, the atomic mass approximately equals the mass number.
same numbers of protons and electrons and behave identically in chemical reactions but they have different numbers of neuutrons.
one isoptope in which the nucleus decays spontaneously, giving off particles and energy.
- An energy level representing the distance of an electron from the nucleus of an atom.
- Electrons occur only at certain energy levels
An attraction between two atoms resulting from a sharing of outer-shell electrons or the presence of opposite charges on the atoms. The bonded atoms gain complete outer electron shells.
atom or molecule with an electrical charge resulting from a gain or loss of one or more electrons
Two ions with opposite charges attract each other; the attraction holds them togeather
exsist as __ in nature
two atoms share one or more pairs of outer-shell electrons
Two or more atoms held together by a covalent bond for a __
atoms share two pairs of electrons
Attraction of a given ato for the electrons of a covalent bond
the more electronegative an atom, the more ___ it pulls shared electrons toward its nucleus
Nonpolar covalent bonds
both atoms exert an equal pull on the electrons - electrons are shared equally between the atoms
polar covalent bond
unequal sharing of electrons
in a polar covalent bond, one atom of the molecule is___ and another is __
charged regions on each water molecule are electrically attracted to oppositely charged regions on neighboring molecules. because the positively charged region in this special type of bond is always a hydrogen atom its called a Hydrogen bond
tendency of molecules to stick together (stronger for water thanmost liquids)
clinging of one substance to another
adhesion of water to the cell walss of a plant's thinveins also helps
counter the downward pull of gravity
Measuere of how difficult it is to stretch or break the surface of a liquid.
Amount of energy associated with the movement of atoms and molecules in a body of matter
measures the intensity of heat - AVERAGE speed of molecules rather than the TOTAL amount of heat energy in a body of matter
Heat is ___ in order to break hydrogen bonds
Heat is ___ whenhydrogen bonds form
whenwater is cooled, there are more hydrogen bonds forming, ___ heat and slowing the cooling process.
Large bodies of water can store a Large amount of heart from the sun during warm periods. In cooler times, the water gives off heat ( keeping coastal areas in a more stable climate ) Water's ____ also stabilizes ocean temperatures.
resistance to temperature
liquid consisting of a uniform mixture of wo or more substances
dissolving agent (usually water)
substance that is dissolved ( sugar, salt milk etc.)
a solution where water is the solvent
In regard to pH levels; chemical compounds that recieve a OH- creates a ___ and then has more (OH- or H+)
In regard to pH levels; chemical compounds that donates a OH- creates a ___ and then has more (OH- or H+)
pH scale stands for
Potential of Hydrogen
On the pH scale; a 1 would be the most __
On the pH scale; a 14 would be the most
Each pH unit represents a #fold exchange in the concentration of H+ in a solution
# ten; tenfold exchange between numbers
biological fluids that minimize changes in pH by accepting or releaseing H+ as needed
refers to rain, snow, or fog with a pH lower than 5.6
30% of CO2 is taken in by the oceans. an ___ of CO2 absorption is expected to change ocean chemistry and harm marine life an ecosystems
CO2 is being absobed due to ___ pH of seawater. which then ___ the concentrationof carbonate ions which are used by coral to protect themselves and by default protect fish and sea creatures. a depleation of coral means less fish and less reprodution.
making and breaking of chemical bonds, leading to changes into the compositon of matter.
result of a chemical reaction
SAME number of atoms must be present of both sides of a chemical reaction equation
No matter can be created nor destroyed.