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bio review ch 2 SCC
chemistry
| Question | Answer |
|---|---|
| which four elements make up 96% of all matter found in organisms? | carbon, oxygen, hydrogen, and nitrogen |
| What is the difference between organic and inorganic molecules? | organic are those who contain carbon, inorganic do not have carbon in them. |
| define atomic weight | average of all mass (only natural occurring) numbers of the isotopes |
| define mass number | protons + neutrons (mass = weight) |
| define isotope | forms of the Same element with different number of neutrons. |
| define atomic number | number of protons |
| define orbitals | groups of electron shell |
| define electron shell | shells that hold electrons and have a specific number of orbitals they hold |
| how many electrons does an orbital hold? | 2 electrons |
| how many orbitals do shell #1, 2, and 3 hold? | #1 holds 1 orbital (2 electrons), #2 holds 4 orbitals (8 electrons), #3 hold 4 or 9 orbitals (8/18 electrons) |
| define valence | number of unpaired electrons on the outer shell |
| define valence shell | outermost shell holding electrons |
| what is the difference between a covalent and an ionic bond? | covalent is when two atoms share electrons and an ionic is where electrons are given, taken, or stolen form atoms to another. |
| define ion | atom of a molecule that carries a charge |
| define cation | atom with a positive charge |
| define anion | atom with a negative charge |
| define electronegativity | tendency of a nucleus to pull electrons to it. oxygen and Florine are highly electronegative. |
| what is the difference between polar and non polar covalent bond? | polar is when electrons or non shared equally, and non polar is when they are |
| what determines the number of bonds an atom can make? | the number of unpaired electrons because they can attach to something |
| define hydrogen bonds | weak electrical attractions between water molecules (can be broken by heat) |
| define hydrophobic | mostly lipids. these molecules are not charged and so does not interact with charged molecules such as water, instead interacts with itself |
| define hydrophilic | atoms and molecules can interact with water |
| what are the four properties of water? | cohesion, adhesion, water is more dense as a liquid than as a solid, water is able to absorb large amounts of water. |
| define specific heat | amount of energy needed to raise the temp. of 1g of h20 by 1^C |
| define heat of vaporization | energy required to change a liquid to a gas |
| define cohesion | binding of like molecules (results in surface tension) |
| define adhesion | binding between unlike molecules |
| define acid | substances that give up protons and raise the hydrogen ion concentration (give up hydrogen ions) 1-7 on the pH scale |
| define base | substances that acquire protons and lower the hydrogen concentration (accept hydrogen ions) 7-14 on the pH scale |
| define buffers | compounds that minimize changes in pH |
| define molecular weight | mass of a molecule (all atoms added up) |
| define molarity | number of moles of a substance in 1L of solution (1 mole = 6.02*10^23) |
| define reactants | initial molecules in a chemical reaction (written on the left) |
| define products | result in a chemical reaction (written on the right) |
| define chemical equilibrium | when the forward and reverse reaction proceed at the same rate |
| what is the difference between endothermic and exothermic reactions? | endo- must add heat, exo- releases heat |
| what is the difference between kinetic and potential energy? | kinetic- energy of motion, potential- stored energy |
| what are the first and second law of thermodynamics? | 1) energy is conserved = cannot be created or destroyed, 2) entropy is always increased in an isolated system. |
| what are the two factors determining if a reaction is spontaneous or not? | 1) the degree of disorder, 2) the amount of potential energy |
Created by:
mtalbot
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