Carboxylic Acids + Lipids 1 Flashcards
Carboxylic Acid Identifiers
Functional group: -COOH. Triagonal planar C, C to C bonds is 120 degrees. Most molecules are associated as dimers due to H bonding. Soluble in water due to H bonding (when chain <5 Cs)
Carboxylic acid reacting with a base
Products: carboxylate (salt) and water
Do carboxylic acids dissociate in water
Yes. Form conjugate base and a positive ion
Carboxylic acids Ka Calculation
([conjugate base] x [positive ion]) / [carboxylic acid]. Note: water is in excess (doesn’t factor into equation).
Relationship between Ka and pKa
pKa = -log(Ka)
Acids Ka and pKa
High Ka = low pKa. Lower pKa = higher Ka = stronger acid
Relationship between acids and their conjugate bases
stronger acid = weaker (more stable) conjugate base
Which conjugate base is stabilised by resonance
Carboxylate. Alkoxide isn’t
Effects of an electron withdrawing group on conjugate base stability
EWG = delocalised charge = less reactive = more stable conjugate base = stronger acid = lower pKa
Effects of electron donating groups on conjugate base stability
EDGs = localised charge = more reactive = less stable base = weaker acid = higher pKa
How do carboxylic acids form water soluble salts
Reaction with strong bases (NaOH and KOH). Carboxylic acid is deprotenated. It’s negatively charged O attracts the positive ion of the base forming a salt. The proton and the remaining negative ion form biproduct
Soaps Mode of action
Soap’s hydrocarbon tail enters oil stain and hydrophobic heads stick out. Hydrophobic heads attreact water to stain
What conditions are required to convert water soluble salt to an amide
High temp (~250 degrees C)
2 classifications of lipids
Can be hydrolysed (contains ester bonds) and can’t be hydrolysed (doesn’t contain ester bonds)
Lipid function in body
Energy source, cell membrane structure and organ protection
Fatty acid Outline
Long (12-20 Cs) linear hydrocarbon chain, carboxylic acids (COOH) with no ester bonds
Saturated Fats Outline
Hydrocarbon chanin where all Cs are saturated (single C-C bonds only). Linear, rotatible molecule. Carboxylic acid denotes where primary C is (end closest)
Unsaturated fats Outline
At least 1 C-C bond is unsaturated (double/triple bond). Cis configuration (substituents of Cs are on the same side). Primary C is 1 furthest away from substituents and double bonds
Polyunsaturated fats outline
Unsaturated fats with more then 1 unsaturated C to C bond. Unstaurated double bonds must always be separated by a methyl group. Eg linoleic acid (omega 6) used to reduce lipid levels in body, reducing heart attack risk
Omega Outline
Denotes first C from methyl end of chain to have an unstaurated bond
Eicosanoids Outline
3 classes: prostaglandins (polyunsaturated fats arcidonicc acid derivatives), Thromboxane and leukotrienes
