Acid-Base Chemistry Quiz

Weak Bases

• A weak base is a substance that donates a pair of electrons to form a coordinate bond, but it does not fully dissociate in water.
• The structure of a weak base differs from antipyrine on the position of the C5-atom.

Henderson-Hasselbalch Equation

• The Henderson-Hasselbalch equation is used to calculate the pH of a solution.
• The equation is pH = pKa + log([A-]/[HA]), where pKa is the negative logarithm of the acid dissociation constant, [A-] is the concentration of the base, and [HA] is the concentration of the acid.
• The equation assumes that the concentration of the acid and base are equal.

pH Calculations

• The pH of a solution can be calculated using the Henderson-Hasselbalch equation.
• For example, the pH of a solution that is 0.30M in ammonia (NH3) and 0.20M in ammonium chloride (NH4Cl) can be calculated using the equation.
• The pH of a 0.2M HCl solution can also be calculated.

Characteristics of Compounds

• Adenine and cytosine are heterocyclic compounds, meaning they have atoms of different elements in their ring structure.
• Purines and pyrimidines can form multiple non-covalent hydrogen bonds.
• Soaps are water-soluble sodium or potassium salts of long-chain fatty acids.
• Triacylglycerols and glycerophospholipids contain fatty acids and are saponifiable.
• Phenol is less acidic than nitrophenol.

Buffer Solutions

• A buffer solution is a solution that resists changes in pH upon the addition of small amounts of acid or base.
• Buffer solutions usually consist of a weak acid with its conjugate base or a weak base with its conjugate acid.
• The Henderson-Hasselbalch equation can be used to calculate the pH of a buffer solution.
• The capacity of a buffer to neutralize added acid or base depends on the concentrations of HA and A- in solution.
• A buffer solution can be made by mixing H3PO4 and NaH2PO4.

Acid-Base Reactions

• The pH of a solution can be affected by the addition of acid or base.
• A solution with a pH of 3 is 1000 times more acidic than a solution with a pH of 6.
• The reaction of hydrochloric acid with a solution containing equal concentrations of acetic acid and sodium acetate results in the formation of CH3COOH.
• Aldehydes readily undergo oxidation, while ketones are resistant to mild oxidation.

Lipids

• Fatty acids are molecules that have a straight chain of an even number of carbon atoms, with hydrogen atoms along the length of the chain and a carboxyl group at one end.
• Triacylglycerols are formed by linking fatty acids with an ester linkage to three alcohol groups in glycerol.
• Saponification is the formation of a metallic salt of a fatty acid, and it involves the treatment of free fatty acids and/or glycerides with a base.
• Ganglioside is a type of membrane lipid that contains an acidic oligosaccharide.

Amino Acids

• At pH 5.5, half of the amino acid molecules have a +1 charge.
• The chemical formula of citric acid includes the groups COOH and OH.

Aldehydes and Ketones

• Secondary alcohols can be oxidized to form ketones.
• Aldehydes can be reduced to form primary alcohols.
• Catalytic dehydrogenation of primary alcohols gives an aldehyde.

Autoionization of Water

• Water can undergo autoionization to form H3O+ and OH ions.
• The equilibrium constant for the autoionization of water, Kw, is 10-14 at 25°C.
• In a neutral solution, [H3O+] = [OH-].
• In an acidic solution, [H3O+] > [OH-].
• In a basic solution, [OH-] > [H3O+].

pH Measurements

• pH can be measured using pH paper, pH meters, or quantitative measures of acidity or basicity.
• pH is a measure of the concentration of hydrogen ions in a solution.

Buffer Capacity

• The buffer capacity of a solution depends on the concentrations of HA and A- in solution.
• A buffer solution can be made by mixing H3PO4 and NaH2PO4.
• The Henderson-Hasselbalch equation can be used to calculate the pH of a buffer solution.

Other

• The structural formula of lactose includes a β-1,4-glycosidic bond.
• Ethanol can be converted to ethanal by oxidation.
• The reaction of propanoic acid and sodium hydroxide produces sodium propanoate and water.
• The products of a reaction between a carboxylic acid and an alcohol are an ester and water.
• Malic acid does not exhibit optical isomerism.