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21 Cards in this Set
- Front
- Back
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What percent of a living organism is comprised of water?
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70 to 95%
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Why is water fluid?
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Because hydrogen bonds are weak so they can break and reform constantly
This can occur due to the polarity of H20 molecules |
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What are the four properties of water that are fundamental for life?
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Cohesive behavior
Ability to moderate temperature Expansion upon freezing Versatility as a solvent |
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How do land plants use water’s cohesive property? How do insects use it?
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Water is able to travel against gravity
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What is specific heat? Does water have a high or low specific heat?
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Specific heat is the energt required to increase the tempeeratyre of 1g of a substance by 1 degree.
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How does the ability of water to moderate temperature help explain the cyclical nature of the ice ages?
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don't know
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Why does water expand upon freezing? How does this property of water protect life forms that live in bodies of water?
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Water expands upon freezing because the hydrogen bonds in ice are more stable and ordered. This means there is more space between them which causes them to be less dense than liquid water. Water is at it's densest at 4*C
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At what temperature is water maximally dense?
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4 degrees C
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What is a hydration shell? About what types of molecules does a hydration shell form?
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When an ionic compound is dissolved in water, each ion is surrounded by a sphere of water molecules. This is know as the hydrate shell.
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Be able to define the terms hydrophilic and hydrophobic. Is oil hydrophilic or hydrophobic? What about table salt?
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Hydrophilic substances like water and hydrophobic substances don't like water. Oil is hydrophobic. Salt is hydrophilic.
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Be able to calculate the hydrogen ion concentration in an aqueous solution at a particular pH. Also be able to calculate the pH of a solution with a particular molar concentration of H+ or OH- ions.
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pH = -log [H+]
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In pure water, about how many molecules are broken apart into hydronium and OH- ions at any given time?
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[H+] {OH-] = 10-14
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Be able to define the terms acid and base.
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Acids increase the H+ concentration of a solution
Bases reduce the H+ concentration of a solution |
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What is a buffer solution and how does it work?
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Buffers are substances that minimize changes in concentration of {H+] and [OH-]
They consist of an acid-base pair that can reversibly combine with H+ It contains a weak acid and it's conjugate base When an acid is added to the solution, the dissociated H+ is consumed to drive the equilibrium backwards. When a base is added, the loss of H+ drives the equilibrium forward Thus, the pH changes less than if the acid or base were added to pure water. |
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What is “organic chemistry?”
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The study of compounds that contain carbon
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What is vitalism? What is mechanism? Which theory does scientific evidence support?
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Vitalism is the idea that organic compounds arise only in living organisms, was disproved when chemists synthesized these compounds in labs from non-living substances.
Mechanism is the view that all natural phenomena (including life) are governed by the same physical and chemical laws. Scientific evidence supports mechanism theory. |
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Be able to predict whether an organic molecule will have a tetrahedral or flat shape.
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If it has a double bond or triple bond, it will be flat. If not, it will be tetrahedral
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Why is carbon able to from so many bonds with so many different types of elements?
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It has 4 valence electrons
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What are isomers? What are the three types of isomers?
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Isomers are same compound written different ways.
The 3 types of isomers are: Structural isomers - different covalent arrangements Geometric isomers - same covalent arrnagement but differ in spatial arrangement Enantiomers - mirror images of each other |
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What evidence from isomers suggests that all living things on Earth evolved from a common ancestor?
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common right/left hand dna
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Be able to list the 7 important functional groups. Also know the chemical properties conferred on a molecule by these functional groups. (Spend a lot of time studying Slides 55-56).
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Hydroxy -OH
Carbonyl CO Carboxyl O--C-OH Amino H-N-H Sulfhydryl -SH Phosphate PO4 Methyl CH3 |
