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66 Cards in this Set

  • Front
  • Back
Anything that occupies space and has mass
Matter
Rock, wood, air, metal, water, animals are examples of
Matter
A pure substance that can not be broken down into other substances by chemical means
Element
(the basic ingredient of matter)
Gold, helium, mercury, oxygen are examples of
Elements
How many elements are essential to life
25
What 4 elements make up 96% of living matter in the body
O - oxygen
C - carbon
H - hydrogen
N - Nitrogen
Elements that make up less than 0.01 percent of body but are still very critical for health
Trace elements
Give an example of an important trace element
Iron or iodine
Where do we get most of the trace elements we need
A balanced diet
Substance containing 2 or more elements that are chemically combined in a fixed state
Compound

(H2O is a compound that always has the same ratio of hydrogen and oxygen)
Each element consists of a single kind of what
Atom
Smallest possible particle of an element
Atom

(from Greek word "atomos" meaning indivisible)
Atoms are made of even smaller components called
Subatomic particles
Subatomic particle with a positive electrical charge
Proton
Subatomic particle with a negative electrical charge
Electron
Subatomic particle that is electrically neutral
Neutron
Which subatomic particles are found inside the nucleus
Protons and neurtons
All atoms of an element have the same number of protons that is known as the elements
Atomic number

(Helium atom has 2 protons and so has an atomic number 2)
What element has the same number of protons in the atom but different numbers of neutrons?
Isotopes
In what kind of isotope does the nucleus decay and break down giving off radiation in the form of matter and energy?
Radioactive isotope
How can radioactive isotopes be useful?
In research and medicine
What part of the atom is the key to how an it reacts with other atoms?
Electrons
They differ in the amount of energy they have and belong to different energy levels
How many electrons can the lowest (nearest the nucleus)energy level hold?
How many in the second level?
2

8
What kind of chemical bond occurs when an atom transfers an electron to another atom?
Ionic bond
What is an example of an ionic bond?
NaCl - table salt or sodium chloride
Atoms that have become electrically charged as the result of gaining or losing electrons are called
Ions
What kind of chemical bond is formed when 2 atoms share electrons
Covalent bond
2 or more atoms held together by covalent bonds form a
Molecule
Changes that result in the formation of one or more new substances are called
Chemical reactions
What is a convenient way to describe a chemical reaction
Chemical formula
The starting materials for a chemical reaction are called
Reactants
The ending materials in a chemical reaction are called
Products
The majority of a cells structure is made of
Water
A molecule in which opposite ends have opposite electric charges
Polar molecule
What is an example of a common polar molecule
Water
A weak attraction between the hydrogen atom of one molecule and a slightly negative atom within another molecule is what type of bond
Hydrogen bond
Tendency of molecules of the same kind to stick to one another
Cohesion
Cohesion is strongest for what kind of liquid
Water
The type of attraction that occurs between unlike molecules is called
Adhesion
How does a tree transport water from the roots up to the leaves
Both cohesion and adhesion
Total amount of energy associated with the random movements of atoms and molecules in a sample of matter
Thermal energy
A measure of hte average energy of random motion of the particles in a substance
Temperature
What happens when a substance is heated
The molecules move faster and cause temperature to rise
Amount of matter in a given volume
Density
Is something in a solid state more or less dense
More dense

**except water
when water becomes ice, it is less dense
A uniform mixture of 2 or more substances
Solution
Table salt mixed into a glass of water forms a
Solution
The substance that dissolves in the other substance is the
Solvent
The substance is dissolved
Solute
When water is used as the solvent, the solution is called
Aqueous solution
(aqua = water)
What is the main solvent inside all cells, in blood, and in plant sap
Water
For chemical processes of life to work correctly, there needs to be a balance of what in the body
Acid and base

H+ hydrogen ions
OH- hydroxide ion
A compound that donates an H+ to a solution
Acid
A compound that removes H+ from an aqueous solution
Base
A pH of 7 is
a. acidic
b. basic
c. neutral
Neutral
How do we describe how acidic or basic a solution is
pH scale
The pH of the solution inside most living cells is close to
7 or neutral
What is the range of the pH scale
0-14

0 = most acidic
14 = most basic
Substances that cause a solution to resist changes in pH
Buffers
How does a buffer work?
By accepting or donating H+ ions to keep pH normal
What is the pH of human blood
7.4
Which of these is not an element?
a. hydrogen
b. carbon
c. water
d. iron
Water - it is a compound of H20
Does Nitrogen -14 or Nitrogen -16 have more protons or neutrons
Neutrons

A radioactive isotope has same number of protons but different number of neutrons
A covalent bond forms when:
a. opposites ions attract
b. protons are shared
c. two atoms share electrons
Two atoms share electrons
Substances formed by a chemical reaction are called:
a. reactants
b. products
c. chemical formulas
d. chemical equations
Products
A solution with a pH of 9 is:
a. acidic
b. basic
c. neutral
d. higher in H+ ions than OH-
Basic