Term
| Define the following : matter, compound, isotope, element, trace element, atom |
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Definition
-anything occupying space that has mass
-substance that consists of two of more different elements
-same # of protons and electrons & behave the same, but have diff # of neutrons
-substance that can't be broken down
-essential to health, but only in small quantities
-smallest unit of matter |
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Term
| What four elements compose 96% of living organisms? |
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Definition
| Oxygen, hydrogen, nitrogen, and carbon |
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Term
| Name 7 other macromolecules important in living things that account for the remaining 4%. |
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Definition
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Term
What are the following trace elements used for in the human body?
a. iron
b. iodine
c. fluorine |
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Definition
a. needed to transport oxygen
b. essential for thyroid health
c. reduces tooth decay |
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Term
| What is goiter? How have we reduced the incidence of goiter in the United States? |
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Definition
| It's the thyroid gland growing to an abnormal size. We have reduced it by adding iodine to table salt. |
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Term
| What does “emergent properties” refer to in describing a compound formed from two or more elements? |
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Definition
| A compound is made of two or more elements but has characteristics different than its' elements; its' whole is different/greater than its' sum. |
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Term
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Definition
| Within the atom's nucleus, charge is +2 |
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Term
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Definition
| orbits the nucleus, charge is -2 |
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Term
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Definition
| Within the nucleus, has no charge |
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Term
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Definition
| The number of protons in an atom |
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Term
| Define atomic mass number. |
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Definition
| The sum of protons and neutrons in the nucleus; same as atomic mass or weight |
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Term
| What is a radioactive isotope? Give an example. Describe how radioactive isotopes can be used in basic research. …in medical diagnosis. ….in medical treatment. |
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Definition
| It's one where the nucleus decays spontaneously. 1. to follow molecules undergo chemical changes 2. used in conjunction with imaging techniques 3. radiation in cancer treatment |
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Term
| What determines the chemical properties of an atom? |
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Definition
| The arrangement of electrons |
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Term
| The farther an electron is from the nucleus the ________its energy. |
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Definition
| The farther an electron is from the nucleus, the greater its energy. |
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Term
| Electrons are found in shells surrounding the nucleus. The first shell can hold a maximum of ______electrons. The outermost shells (other than the first) hold a maximum of ______electrons. |
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Definition
| First is full with two. Outermost are full with 8. |
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Term
| Atoms that have outer shells which are full are chemically inert. What does this mean? |
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Definition
| It means those elements are unreactive |
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Term
| When electrons are transferred between elements what type of bond is formed? What holds the atoms in this type of bond together? |
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Definition
| Ionic bonds; the opposite charges attract each other |
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Term
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Definition
| atom/molecule whose electrical charge results from a gain/loss of one or more electrons |
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Term
| A synonym for an ionic compound is _________. |
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Definition
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Term
| How is a covalent bond different from an ionic bond? What do we call the atoms bonded together in this way? |
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Definition
| Two atoms share their outer electrons instead of gaining or losing them. They are called molecules. |
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Term
| How do you indicate a single bond of a covalent bond in a structural formula? A double bond? A triple bond? |
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Definition
| One pair of electrons, two pairs, three pairs, etc. |
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Term
| Why is hydrogen, oxygen, as well as a few other kinds of molecules such as iodine and nitrogen, not considered compounds? |
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Definition
| They are molecules, but only of one element |
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Term
| Define electronegativity. |
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Definition
| The atom's attraction for shared electrons. (Electronegativity=atom pulling electrons toward nucleus.) |
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Term
| What atoms compose a water molecule? What is their structure in this molecule and why is it like this? |
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Definition
| Two hydrogen atoms covalently bonded to an oxygen atom. It's a polar molecule so it has an unequal distribution of charges. |
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Term
| The unequal sharing of electrons produces a _________ _________ _________. |
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Definition
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Term
| What are hydrogen bonds? Are they considered weak or strong bonds? |
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Definition
| Hydrogen atoms part of polar covalent bonds; they are weak bonds. |
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Term
| The three physical states of water are a _______,_________, and a _________. |
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Definition
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Term
| What is cohesion in water molecules and what causes this? Give an example of the importance of cohesion in nature. |
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Definition
| It is the tendency of water molecules to stick together. Its' used in nature for the transport of water in hydrating plants. |
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Term
| Distinguish between heat and temperature. |
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Definition
-amount of energy from movement of atoms and molecules in a body of matter
-intensity of heat; avg speed of molecules |
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Term
| How does sweating cool you? |
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Definition
| By evaporative cooling; the liquid on the surface cools the molecules with greatest energy (hottest ones). |
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Term
| Why does a large body of water not change temperature rapidly? Why is this important in the ocean or a lake? |
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Definition
| Water resists changes to temperature; energy must disrupt hydrogen bonds for the temperature to change. |
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Term
| Why is ice less dense than liquid water? |
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Definition
| Because ice has fewer hydrogen bonds than liquid water. |
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Term
| Why does the freezing of water crack boulders? |
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Definition
| Water expands as it freezes. If water gets into the crevice of a boulder and expands, the boulder will crack. |
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Term
| What is a solution? Distinguish between the solute and solvent. |
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Definition
Its' a mix of two or more substances.
-substance its' dissolved in
-dissolving agent |
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Term
| What do we mean by saying that “water is the solvent of life” |
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Definition
| Because of water's versatility as a solvent |
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Term
| What characteristic of water allows it to be such a good solvent? |
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Definition
| The polarity of its' molecules |
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Term
| When chemical compounds contribute additional hydrogen ions (H+) to an aqueous solution; this solution is called an ________. When chemical compounds accept hydrogen ions or remove them from the solution (often by donating hydroxide ions (OH-); this solution is called a ___________. |
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Definition
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Term
| What do we use to describe how acidic or basic a solution is? |
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Definition
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Term
| When solutions have a pH of 7 they are considered __________ |
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Definition
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Term
| What are buffers and their role in organisms? Give an example. |
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Definition
| Substances that minimize changes in pH; they can control stability in blood and other internal organs. |
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Term
| Compared to a basic solution at a pH of 8, the same volume of an acidic solution at a pH of 5 has _______times more hydrogen ions. Compared to a strong acidic solution at a pH of 3, the same volume of a weaker acidic solution at a pH of 5 has ______times less hydrogen ions. |
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Definition
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Term
| Give an example of how acid precipitation affects the environment. What causes acid precipitation? |
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Definition
| It's caused by large amounts of carbon dioxide in the atmosphere, mostly from burning fossil fuels. It has killed marine life, changed soil chemistry, and affected forests. |
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Term
| What does the arrow indicate in a chemical equation? |
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Definition
| It indicates a conversion of chemicals and distinguishes between the reactants and product. |
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Term
| What do the numbers used a subscripts indicate in an equation? |
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Definition
| The number of the preceding element |
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Term
| What do the numbers used in front of an atom or molecule in an equation represent? |
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Definition
| Number of atoms or molecules |
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