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66 Cards in this Set
- Front
- Back
Anything that occupies space and has mass
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Matter
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Rock, wood, air, metal, water, animals are examples of
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Matter
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A pure substance that can not be broken down into other substances by chemical means
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Element
(the basic ingredient of matter) |
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Gold, helium, mercury, oxygen are examples of
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Elements
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How many elements are essential to life
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25
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What 4 elements make up 96% of living matter in the body
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O - oxygen
C - carbon H - hydrogen N - Nitrogen |
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Elements that make up less than 0.01 percent of body but are still very critical for health
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Trace elements
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Give an example of an important trace element
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Iron or iodine
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Where do we get most of the trace elements we need
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A balanced diet
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Substance containing 2 or more elements that are chemically combined in a fixed state
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Compound
(H2O is a compound that always has the same ratio of hydrogen and oxygen) |
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Each element consists of a single kind of what
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Atom
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Smallest possible particle of an element
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Atom
(from Greek word "atomos" meaning indivisible) |
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Atoms are made of even smaller components called
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Subatomic particles
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Subatomic particle with a positive electrical charge
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Proton
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Subatomic particle with a negative electrical charge
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Electron
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Subatomic particle that is electrically neutral
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Neutron
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Which subatomic particles are found inside the nucleus
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Protons and neurtons
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All atoms of an element have the same number of protons that is known as the elements
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Atomic number
(Helium atom has 2 protons and so has an atomic number 2) |
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What element has the same number of protons in the atom but different numbers of neutrons?
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Isotopes
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In what kind of isotope does the nucleus decay and break down giving off radiation in the form of matter and energy?
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Radioactive isotope
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How can radioactive isotopes be useful?
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In research and medicine
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What part of the atom is the key to how an it reacts with other atoms?
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Electrons
They differ in the amount of energy they have and belong to different energy levels |
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How many electrons can the lowest (nearest the nucleus)energy level hold?
How many in the second level? |
2
8 |
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What kind of chemical bond occurs when an atom transfers an electron to another atom?
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Ionic bond
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What is an example of an ionic bond?
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NaCl - table salt or sodium chloride
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Atoms that have become electrically charged as the result of gaining or losing electrons are called
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Ions
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What kind of chemical bond is formed when 2 atoms share electrons
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Covalent bond
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2 or more atoms held together by covalent bonds form a
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Molecule
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Changes that result in the formation of one or more new substances are called
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Chemical reactions
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What is a convenient way to describe a chemical reaction
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Chemical formula
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The starting materials for a chemical reaction are called
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Reactants
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The ending materials in a chemical reaction are called
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Products
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The majority of a cells structure is made of
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Water
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A molecule in which opposite ends have opposite electric charges
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Polar molecule
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What is an example of a common polar molecule
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Water
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A weak attraction between the hydrogen atom of one molecule and a slightly negative atom within another molecule is what type of bond
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Hydrogen bond
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Tendency of molecules of the same kind to stick to one another
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Cohesion
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Cohesion is strongest for what kind of liquid
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Water
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The type of attraction that occurs between unlike molecules is called
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Adhesion
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How does a tree transport water from the roots up to the leaves
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Both cohesion and adhesion
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Total amount of energy associated with the random movements of atoms and molecules in a sample of matter
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Thermal energy
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A measure of hte average energy of random motion of the particles in a substance
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Temperature
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What happens when a substance is heated
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The molecules move faster and cause temperature to rise
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Amount of matter in a given volume
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Density
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Is something in a solid state more or less dense
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More dense
**except water when water becomes ice, it is less dense |
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A uniform mixture of 2 or more substances
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Solution
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Table salt mixed into a glass of water forms a
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Solution
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The substance that dissolves in the other substance is the
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Solvent
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The substance is dissolved
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Solute
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When water is used as the solvent, the solution is called
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Aqueous solution
(aqua = water) |
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What is the main solvent inside all cells, in blood, and in plant sap
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Water
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For chemical processes of life to work correctly, there needs to be a balance of what in the body
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Acid and base
H+ hydrogen ions OH- hydroxide ion |
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A compound that donates an H+ to a solution
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Acid
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A compound that removes H+ from an aqueous solution
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Base
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A pH of 7 is
a. acidic b. basic c. neutral |
Neutral
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How do we describe how acidic or basic a solution is
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pH scale
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The pH of the solution inside most living cells is close to
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7 or neutral
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What is the range of the pH scale
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0-14
0 = most acidic 14 = most basic |
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Substances that cause a solution to resist changes in pH
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Buffers
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How does a buffer work?
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By accepting or donating H+ ions to keep pH normal
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What is the pH of human blood
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7.4
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Which of these is not an element?
a. hydrogen b. carbon c. water d. iron |
Water - it is a compound of H20
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Does Nitrogen -14 or Nitrogen -16 have more protons or neutrons
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Neutrons
A radioactive isotope has same number of protons but different number of neutrons |
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A covalent bond forms when:
a. opposites ions attract b. protons are shared c. two atoms share electrons |
Two atoms share electrons
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Substances formed by a chemical reaction are called:
a. reactants b. products c. chemical formulas d. chemical equations |
Products
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A solution with a pH of 9 is:
a. acidic b. basic c. neutral d. higher in H+ ions than OH- |
Basic
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