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38 Cards in this Set
- Front
- Back
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What 4 elements make up approx. 96% of living matter? |
* Carbon * Hydrogen * Oxygen * Nitrogen |
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What trace element is required by humans, and other vertebrates, and not by other organisms such as bacteria or plants? |
* Iodine |
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Virtually all organisms require the same elements in the same quantities. TRUE OR FALSE? |
False |
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Why is each element unique and different from other elements in chemical properties? |
Each element has a unique amount of protons in its nucleus. |
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What is the atomic mass of each element made of? |
The number of protons + neutrons in an element. |
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In what way are elements in the same column of the periodic table the same? |
They have the same number of electrons in their valence shell. |
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Oxygen has an atomic number of 8 and a mass number of 16. What is the atomic mass of an oxygen atom? |
Approx. 16 daltons |
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What is the most common isotope? (isotope: different atomic forms of the same element) |
Carbon-12 |
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Why does a mole of carbon in naturally occurring coal weigh slightly more than 12 grams? |
Some carbon atoms have more neutrons |
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Difference between carbon-12 (12/6C) is that carbon-14 (14/6C) has... |
carbon-12 has 2 more neutrons than carbon-14. |
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An atom has 6 electrons in its outer shell. How many unpaired electrons does it have? |
Missing (2) electrons in outer shell to make 8. |
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Atomic number of nitrogen is 7. Nitrogen-15 is heavier than nitrogen-14 because the atomic nucleus of nitrogen-15 contains how many neutrons. |
8 neutrons. Original is 7, Nitrogen-15 is heavier and contains 8 more neutrons. |
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Electrons exist only at fixed levels of potential energy. However, if an atom absorbs sufficient energy, a possible result is that... |
an electron may move to an electron shell farther away from the nucleus. |
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From its atomic number of 15, it is possible to predict that the phosphorus atom has... |
15 protons and 15 electrons. |
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What atom has the same valence (number of electrons in outer shell) as carbon 12/6C. |
14Si silicon |
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Two atoms appear to have the same mass number. These atoms... |
must have the same protons and neutrons. |
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Fluorine has an atomic number of 9 and a mass number of 19. How many electrons are needed to complete the valence shell of a fluorine atom? |
Missing 1 electron in outer shell to complete valence shell. Needs 10 total electrons in atom to complete two valence shells. |
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What is the maximum number of electrons in a single 2p orbital of an atom? |
2. Only 2 can be in the first valence shell of an atom. |
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If phosphorus-32 ( atomic number 15) undergoes a form of radioactive decay where a neutron turns into a proton and then lets off radiation in the form of an electron, what does it turn into? |
sulfur-32 (atomic number 16) |
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An atom with atomic number 12 would have what type of chemical behavior in bonding with other elements? |
It would form ions with a +2 charge. |
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If a salamander relied on hydrogen bonds to cling to surfaces, what type of surface would cause the most problems for this animal? |
surface made of carbon and hydrogen atoms covalently bonded together. |
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A covalent chemical bond is one in which |
outer-shell electrons of two atoms are shared so as to satisfactorily fill the outer electron shells of both atoms. |
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What is the maximum number of covalent bonds an element with atomic number of 8 can make. |
2 covalent bonds |
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Nitrogen (N) is much more electronegative than Hydrogen (H). What is correct about the atoms in Ammonia? |
Each hydrogen atom has a partial positive charge; the nitrogen atom has a partial negative charge. |
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when two atoms are equally electronegative, they will interact to form. |
nonpolar covalent bond |
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What results from an unequal sharing of electrons between atoms? |
polar covalent bond |
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A covalent bond is likely to be polar when |
one of the atoms sharing electrons is much more electronegative than the other atom |
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Which molecules contains the most polar covalent bonds? |
- H2? -O2? -CO2? -H2O? -CH4? |
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In ammonium chloride salt (NH4Cl) the anion is a single chloride ion, Cl. What is the cation of NH4Cl? |
NH4, with a charge of +1. |
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The atomic number of chlorine is 17. The atomic number of magnesium is 12. What is the formula for magnesium chloride? |
MgCl2 |
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How many electron pairs are shared between carbon atoms in a molecule that has the formula C2H4? |
2 electron pairs |
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Which bond or interaction would be difficult to disrupt when compounds are put into water? |
covalent bond |
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What explains most specifically the attraction of water molecules to one another? |
hydrogen bond |
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Van der Waals interaction result when.. |
Electrons are not systematically distributed in a molecule |
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What would be regarded as compounds? |
-H20, O2, ad CH4 -H2O and O2 -O2 and CH4 -CH4 and O2, but not H2O -H2O and Ch4, but not O2 |
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What is true for this reaction? 3 H2 + N2 <---> 2 NH3 |
being formed and decomposed |
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What correctly describes chemical equilibrium? |
When forward and reverse reactions continue with no effect on the concentrations of the reactants and products. |
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What describes any reaction that has reached chemical equilibrium? |
The rate of the forward reaction is equal to the rate of the reverse reaction. |
