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Ch. 2 - Chemical Basis of Life
10/26 Test- Mrs. Feinman
56
Science
10th Grade
10/25/2011

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Term
Matter is composed of ______. _______ cannot be broken down to other substances
Definition
chemical elements

elements
Term
A _______ is a substance consisting of two or more elements in a fixed ratio
Definition
compound
Term
There are __ elements essential to life, but only these four make up 96.3% of the human body. These four elements are...
Definition
Oxygen, Carbon, Hydrogen, and Nitrogen.
Term
These six elements make up 3.7% of the human body...
Definition
Calcium, Phospherous, Sulfer, Sodium, Chlorine, and Magnesium
Term
_____ elements are essential to the body, but only in miniscule amounts
Definition
trace elements
Term
Chemicals are added to foods to ____,_____, and ___
Definition
preserve it, make it more nutritious, and make it look better
Term
What are the three subatomic particles and what are their charges?
Definition
proton-positive-in nucleus
neutron-neutral-in nucleus
electron-negative-out of nucleus
Term
Name pros and cons of Radioactive tracers
Definition
Radioactive can be used in medical procedures to help find a patient's diagnosis, but however it cause damage to a person's DNA and create abnormal bonds in the body
Term
The _____ kind of chemical bond is the covalent bond, in which.....
Definition
two atoms share one or more pairs of outer-shell electrons
Term
two or more atoms held by covalent bonds form a ______.
Definition
molecule.
Term
An atom's attraction for shared electrons is called it's _______.
Definition
electronegativity
Term
The bonds in some molecules are said to be ______ because _____ are shared equally between the atoms.
Definition
nonpolar covalent bonds, electrons
Term
The bonds in some molecules are said to be ______ because the _____ are shared unevenly
Definition
polar covalent bonds, electrons
Term
A molecule is polar when...
Definition
it has an uneven distribution of charges
Term
An ion is an atom or molecule with...
Definition
an electrical charge resulting from a gain or loss of electrons
Term
When attraction holds ions together, it is called a ____
Definition
ionic bond
Term
_____ affects the strength of ionic bonds
Definition
environment
Term
A hydrogen atom that has formed a polar covalent bond with an electronegative atom has a partial ______ charge
Definition
positive
Term
A chemical reaction is...
Definition
The breaking and making of chemical bonds leading to changes in the composition of matter
Term
An arrow indicates the conversion of the starting materials (in chemical equation), called the _____
Definition
reactants
Term
The material resulting from a chemical reaction
Definition
product
Term
The raw materials of photosynthesis are _______ and _______.
Definition
carbon dioxide and water
Term
_____ bonds make liquid water _____
Definition
Hydrogen, cohesive
Term
The tendency of molecules of the same kind to stick together is called ______. ______ is stronger for _____ then most other liquids
Definition
cohesion

cohesion, water
Term
Most plants rely upon _____ to help transport water and nutrients from their roots to their leaves
Definition
cohesion
Term
The tendency of one substance to cling to another is called...
Definition
Adhesion
Term
Related to cohesion, _______ is....
Definition
surface tension is the measure of how difficult it is to stretch or break the surface of a liquid.
Term
______ bonds give water high surface tension
Definition
Hydrogen
Term
Heat is....
Definition
the amount of energy associated with the movement of atoms and molecules in a body of water
Term
Temperature is...
Definition
the measure of intensity pf heat- more the speed of molecules rather then the total amount of energy in a body of matter
Term
When molecules with the greatest energy leave, the process of _________ occurs
Definition
evaporative cooling
Term
Heat is released when _______ form, and heat must be absorbed to break ______
Definition
hydrogen bonds (BOTH)
Term
Water can exist as a ___,____, or ___
Definition
water, liquid, or gas
Term
Water is less dense as ice then a liquid because of ______. As water freezes, each molecule forms a stable ____ with it's neighbors. As the ice crystals form, the molecules become _________ than in liquid water.
Definition
hydrogen bonds,
hydrogen bond,
less densely packed
Term
Water can exist as a ___,____, or ___
Definition
water, liquid, or gas
Term
Water is less dense as ice then a liquid because of ______. As water freezes, each molecule forms a stable ____ with it's neighbors. As the ice crystals form, the molecules become _________ than in liquid water.
Definition
hydrogen bonds,
hydrogen bond,
less densely packed
Term
A solution is....
Definition
a liquid consisting of a uniform mixture of two or more substances
Term
The ____ is the dissolving agent in a solution
Definition
solvent
Term
The substance in a solution that is dissolved is the ______
Definition
solute
Term
An ___________ is a solution in which water is the solvent
Definition
aqueous solution
Term
Water's versatility as a solvent results from the _____ of it's molecules
Definition
polarity
Term
A compound doesn't need to be _____ to dissolve in water
Definition
ionic
Term
Hydrogen (___) and Hydroxide (___) ions are very reactive
Definition
H+,
H-
Term
A compound that donates H+/Hydrogen ions to solutions is called an ____
Definition
acid
Term
A ____ is a compound that accepts hydrogen ions and removes them from the solution
Definition
base
Term
We use the ________ to determine how acidic or basic a ________ is
Definition
pH scale, solution
Term
Each pH unit represents a 10_fold change in the ________ in ___ in a solution
Definition
concentration, H+
Term
Buffers are.....
Definition
substances that minimize changes in pH
Term
The pH scale is a ___ point scale. At the most ____ end is battery acid, while at the other end the most ____ is oven cleaner
Definition
acidic, basic
Term
the pH of human blood plasma is very close to __ on the pH scale
Definition
7.4
Term
________ refers to rain, snow, or fog with a pH lower then 5.2. This has affected life in lakes and streams, affected the soil, and affected plant life.
Definition
Acid precipitation
Term
Acid precipitation is caused by _______ and _______ released by burning fossil fuels that react with _____ in the air to from strong ____ that fall to Earth in rain or snow.
Definition
sulfer oxides,
nitrogen oxides,
water,
acids
Term
______ is the main product of burning fossil fuels, and ___% of it is absorbed by oceans. This causes _________.
Definition
Carbon dioxide,
25%,
ocean acidification
Term
Ocean acidification is when CO2 dissolves in water which lowers water's pH level because the CO2 ____ with water to _____ ________
Definition
reacts,
produce,
carbonic acid
Term
(in ocean acidification) The change in acidity decreases the ________ of carbonate ions, which are needed by corals and other organisms to go through a process called ____ they go through as to live. Corals and other such organisms are eaten by fish like salmon and herring.
Definition
concentration,
calcification
Term
Finding evidence of life elsewhere would support the hypothesis that ______ of life is possible
Definition
chemical evolution
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