Chemistry for Physiology
A blood concentration of glucose that is indicative of diabetes is 12 mmol/L. What % concentration of glucose is this equivalent to? (The formula for glucose is C6H12O6; atomic mass of C = 12, H = 1, O = 16; mass of a mole = sum of masses of atoms in formula.)
0.012%
0.216%
5%
12%
0.216%
(By calculation) Percent concentration refers to how many grams are dissolved in 100 ml of solution.One mole of glucose has a mass of 180 g. (6 ร 12) + (12 ร 1) + (6 ร 16) = 180.12 mmol/L = 0.012 mol/Lmol/L = (mass/L)รท(mass of 1 mol): hence 0.012 mol/L = (mass/L)รท180; so mass = 180 ร 0.012 = 2.16 g/ L2.16 g/L = 0.216 g/100 ml = 0.216%(Alternatively: The answer can’t be 5% as this is an isotonic glucose solution. Hence neither is it 12% as this is hypertonic. % conc is not the same number as mol/L, so the answer is not A.)
0.216% (By calculation) Percent concentration refers to how many grams are dissolved in 100 ml of solution.One mole of glucose has a mass of 180 g. (6 ร 12) + (12 ร 1) + (6 ร 16) = 180.12 mmol/L = 0.012 mol/Lmol/L = (mass/L)รท(mass of 1 mol): hence 0.012 mol/L = (mass/L)รท180; so mass = 180 ร 0.012 = 2.16 g/ L2.16 g/L = 0.216 g/100 ml = 0.216%(Alternatively: The answer can’t be 5% as this is an isotonic glucose solution. Hence neither is it 12% as this is hypertonic. % conc is not the same number as mol/L, so the answer is not A.)
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D. The patient has insufficient acid.
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A. The pH of a buffer does not change on addition of acid or base.
B. A buffer has two components which may be a weak acid and its salt.
C. A buffer has two components which may be a weak base and its salt.
D. pH of a buffer depends only on the ratio of its components.
What may be stated about a chemical bond between atoms that is polar? They occur:
A. Between a metal and a non-metal atom
B. Between two non-metal atoms
C. Between two non-metal atoms that are different to each other
D. When the electrons in the bond are shared equally
The diffusion of water molecules across a cell membrane from the side where the solution concentration is more dilute to the side where it is greater is known as which of the following?
A. Osmosis
B. Filtration
C. Hydrolysis
D. Buffer action
Consider a volume of 100 ml of each of the four solutions below. Which would contain the greatest number of osmoles of dissolved particles? (FYI the atomic masses of H = 1, C = 12, O = 16, Na = 23, Cl = 35.5)
A. 5% ethanol: C2H6O
B. 5% glucose: C6H12O6
C. 5% sodium chloride: Na+ Clโ
D. 10% glucose: C6H12O6
What distinguishes an osmole from a mole?
A. In a sample of substance, the number of osmoles is twice the number of moles.
B. Both mole and osmole may be used in reference to ionic compounds, while covalent compounds are described by mole alone.
C. The mass of a mole is the sum of the relative atomic masses (RAM) of the atoms in the formula stated as grams. An osmole is half of this mass.
D. An osmole applies only to covalent molecular substances, whereas a mole is validly applied to both covalent and ionic substances.
Which statement is INCORRECT? Colloid osmotic pressure:
A. Is the difference in solution concentration between plasma and interstitial fluid
B. Refers to the greater solution concentration of plasma, compared to interstitial fluid, due to the plasma proteins
C. Causes water to be drawn into blood from the interstitial fluid
D. Is the pressure exerted on capillary walls due to the collision of the plasma proteins
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