Question

8) The pH of human blood is primarily maintained at 7.4 by A) ATP B) a bicarbonate buffer system. C) carbon dioxide-carbonic acid buffer systems. D) B and C. E) A, B and C. 9) The H+ (or H30+) in cells is the same concentration as that of undissociated water. A) Trure B) False 10) A pharmaceutical company hires a chemist to analyze the purity of the water being used in its drug preparations. If the water is pure, the chemist would expect to find A) only H+ ions and OH-ions. B) H2O molecules and H+ ions. C) H2O molecules, H+ ions, or OH-ions. D) only molecules of H20. E) None is correct 11) (a) If 0.5 mole of glucose weighs 90 g, what is the molecular weight of glucose? 180 daltons (b) 189 daltons (c) 190 daltons (d) 199 daltons

Answer 1

Correct choices/answers are written below with corresponding question numbers-

8. B) a bicarbonate buffer

note - this bicarbonate buffer is made up of Carbonic acid (weak acid) and Bicarbonate (base)

9. B) False

note - blood has H⁺ concentration of about 10^-7.4 and un-dissociated water has H⁺ concentration of about 10^-7. These two values are comparable true, but are not the same.

10. C) H₂O molecules or H⁺ or OH^- ions

11. A) 180 dalton

note - the dalton (symbol - Da) is a lesser used unit of molar mass. 1 dalton is aproximated to be 1 g/mol.

From the given information, we know that 0.5 moles of glucose weighs 90g. Multiplying this by 2 gives 180 (90g*2=180g). 1 mole has gram molecular weight of a molecule. Hence we can say that 1 mole of glucose has 180 g/mol or 180 dalton