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49 Cards in this Set
- Front
- Back
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Living organisms are composed of how many chemical elements |
25 chemical elements |
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Living organisms are composed of? |
Matter |
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What is considered matter? |
anything that occupies space and has mass (weight) |
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A substance that cannot be broken down to other substances is considered an? |
Elements |
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Four main elements in the human body |
Oxygen, Carbon, Hydrogen and Nitrogen |
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Life requires ~ 25 essential elements; some are called? |
Trace Elements |
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Some trace elements are required to prevent disease such as |
Iron and iodine |
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A substance consisting of two or more different elements combined in a fixed ratio are called? |
Compounds |
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Many of the compounds in living organisms contain. |
Carbon, hydrogen, oxygen and nitrogen |
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The smallest unit of matter that still retains the properties of a element |
Atom |
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What has a single positive electrical charge? |
Proton |
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What has a single negative electrical charge? |
Electron |
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What is electrically neutral? |
Neutron |
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Neutrons and protons are packed in the atom’s? |
Nucleus |
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The number of protons is the atom’s? |
Atomic number (blue number in the periodic table) |
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The sum of the protons and neutrons in the nucleus is the? |
Mass number |
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There are variations, which have the same # of protons and electrons but different # of neutrons, they are called? |
Isotopes such as Carbon-13 &14 |
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What is an imaging technique that detects the location of injected radioactive materials? |
Positron-emission tomography (PET) |
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If chemical bonds are broken what is being emitted? |
Energy, which causes abnormal bonds to form (Mutation) |
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Electrons occur in energy levels called? |
Electron Shells |
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Only electrons are involved in chemical activity. True or False |
True |
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How many electron are housed in the second and third shell? |
Eight |
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How many electrons are housed in the first shell? |
Two |
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When atoms share, donate, or receive e- (electrons) its called? |
Chemical Bonds |
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Ionic bonds are? |
Attractions between ions of opposite charge |
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An atom or molecule with an electrical charge resulting from gain or loss of electrons is called an? |
Ion |
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What results when atoms share outer- shell electrons? |
A covalent bond |
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What is formed when atoms are held together by covalent bonds? |
A molecule |
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Atoms are most stable when their outer shell is full. True or False? |
True |
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The attraction (pull) for shared e- is called? |
electronegativity |
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In molecules of only one element, the pull toward each atom is equal, because each atom has the same electronegativity, the bonds formed are called? |
nonpolar covalent bonds |
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Unequal e- (electrons) sharing creates polar molecules the result is a? |
polar covalent bond |
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Molecules with this unequal distribution of charges are called |
polar molecules |
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H2O molecules are electrically attracted to oppositely charged regions on neighboring molecules because the positively charged region is always a H+ atom, the bond is called a? |
Hydrogen bond |
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H+ bonding causes molecules to stick together " This property is called? |
Cohesion |
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Cohesion is related to? |
surface tension |
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What is the energy associated with movement of atoms and molecules in matter? |
Heat |
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What measures the intensity of heat? |
Temperature |
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What is a liquid consisting of a uniform mixture of two or more substances |
A solution |
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The dissolving agent of a solution is? |
The solvent |
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The substance of a solution that is dissolved is? |
The solute |
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Energy of motion is? |
Kinetic energy |
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Stored energy is? |
Potential energy |
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Potential energy stored in chemical bonds? |
Chemical energy |
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Enzymes do not "speed up" reactions they? |
lower the activation energy required for the action to proceed. |
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Synthesis reaction: |
A + B → AB (dehydration reaction) |
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Decomposition reaction: |
AB → A + B (hydrolysis) |
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The formation of water from hydrogen and oxygen is an example of a? |
chemical reaction |
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The reactants (H2 and O2) are converted to? |
H2O, the product |
