Exam 1 Chapter Overviews

Exam 1 Chapter Overviews - Chapter 3 A water molecule is...

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Chapter 3 A water molecule is composed of covalent bonds, but hydrogen bonds connect water molecules to one another. Water has electronegativity (can attract other compounds with opposing charges) and is polar Heat must be absorbed in order to BREAK hydrogen bonds, and heat is released when hydrogen bonds form (makes sense because when hydrogen bonds form the substance is more stable, so energy is released when this happens) Buffers pH = pKa + log (base/acid) Acids are H+ donors: they respond to a rise in pH by dissociating into a base and H+ ions Bases are H+ acceptors: they response to a drop in pH by combining with H+ to form an acid Normal rainwater is slightly acidic because of carbonic acid When water vaporizes, hydrogen bonds between water molecules break. Evaporative cooling is the absorption of heat by the breaking of hydrogen bonds. Chapter 4 Hydrocarbons are made of only hydrogen and carbon. They are nonpolar, hydrophobic, and good sources of stored energy (petroleum/gasoline). They are called alcanes Methane- 1 carbon; Ethane- 2 carbons; Propane- 3 carbons; Butane- 4 carbons -Enes have double bonds and are flat Isomers : have the same chemical composition but different bonds/structures different properties Structural Isomers differ in the covalent arrangement of their atoms (may just be one double bond) Geometric Isomers have the same covalent partnerships, but they differ in their spatial arrangements ( cis - same molecules on same side and trans - same molecules on different sides). There must be a double bond between the two carbons in the middle Enantiomers : exact same composition and structure but they are opposites—superimposible Propane cannot form structural isomers Functional groups (see table in SI review sheet) – all are hydrophilic/water soluble Hydroxyl (--OH): ‘alcohols’; forms H-bonds, is polar Carbonyl (--C=O): found in sugars; ketones are carbonyl groups within the carbon skeleton and aldehydes are carbonyl groups on the end of the carbon skeleton Carboxyl (--COOH): acids (H+ donors) Amino (--NH 2 ): basic (H+ acceptors) Sulfhydryl (--SH): ‘thiols’; forms disulfide bridges, which stabilize protein structure Phosphate (PO 4 2- ): contributes a negative charge; can react with water—it does this in ATP; acts as an acid Asymmetric Carbon : must have four DIFFERENT atoms or groups of atoms attached to it. There may be several asymmetric carbons in a carbon chain Chapter 5 Covalent bonds join monomers together to form polymers CARBOHYDRATES (multiples of CH 2 O) Classifying monosaccharides
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Carboxyl group location (aldoses have it at the end of the carbon chain, ketoses have it within the carbon chain) Length of the carbon skeleton (“trioses” are 3-carbon sugars)
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Exam 1 Chapter Overviews - Chapter 3 A water molecule is...

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