Chemistry for Physiology

This is a definition of an acid.

A base has the ability to produce hydroxide ions when added to water.

The name may be guessed at, but it is possible for two substances to have the same formula but a different structure. Glucose and fructose both have this formula.

A neutralisation reaction involve stomach acid (hydrochloric acid) reacting with a base (calcium carbonate is a weak base) to produce a salt (calcium chloride) and water. Choice D is wrong as calcium carbonate does not appear as a reagent.

Monohydrogen phosphate is the species that destroys acid (by accepting a hydrogen ion from the acid). Blood pH would decrease very slightly as the concentration of monohydrogen phosphate decreases slightly and the concentration of dihydrogen phosphate increases slightly.

0.18% = 0.18 g per 100 ml, so in 1000 ml, there would be 10 × 0.18 = 1.8 g.

The solvent dissolves (e.g. water); the solute (e.g. salt) is dissolved

Ionic substances (e.g. Na⁺Cl−) separate into ions when dissolved. Hence a mole of NaCl would produce two osmoles of ions (1 mol of Na ions and 1 mol of Cl ions). Hence half of a mole of NaCl, when dissolved, would result in one osmole of dissolved particles (ions).

The pH of a buffer is determined by the ratio of its two components. pH is a logarithmic scale of the hydronium ion concentration of a solution. Hence the ratio must change by a factor of 10 in order for the pH to change by one (i.e. change from 7.4 to 8.4).

Acids have low pH (less than 7). The stomach contents contain hydrochloric acid secreted by the parietal cells of the gastric glands so typically has a pH of less than 2.0. Urine, while usually acidic, rarely falls below pH of 5.