Medical chemistry and biochemistry
1. Calculations (conversions of units, osmolarity, preparation of solutions, molarity x
density)
1. Convert the following values into units mentioned in parentheses.
a) 1700 ng/mL → (mg/L)
[1.7 mg/L]
b) 60 pmol/µL → (mmol/L)
[0.06 mmol/L]
c) 0.95 mg/mL → (g/L)
[0.95 g/L]
d) pO2 = 115 mmHg → (Torr)
[115 Torr]
e) pCO2 = 61.8 mmHg → (kPa)
[8.2 kPa]
f) 180 kcal → (kJ)
[753.6 kJ]
2. Calculate the concentration of osmotic effective particles in MgCl2 solution with
molar concentration 0.3 M.
[0.9 osmol/L]
3. The osmolarity of Na2HPO4 solution is 0.9 osmol/L. What is the molarity of this
solution?
[c = 0.3 mol/L]
4. Calculate the concentration of osmotic effective particles in 0.1 M NaCl solution in
mosm/L.
[200 mosm/L]
5. Native erythrocytes were placed into the following solutions:
a) 0.3 M glucose
b) 0.3 M NaCl
c) 0.15 M glucose
d) 0.15 M NaCl
Osmolarity of erythrocyte cytoplasm is 0.3 osm/L.
In which solution(s) (mentioned above) a water will pass into erythrocytes and these
cells will be damaged?
[c) it is a hypotonic solution]
6. If the number of moles of toluene is 0.66 mol, what is the volume (in cm 3) of the
toluene? Density of toluene = 0.88 g/cm3, Mr (toluene) = 92
[V = 69 cm3]
7. How many milligrams of glucose are required for preparation 0.15 L of a 12
mmol/L solution? Mr (glucose) = 180
[324 mg]
8. If 50 μL of uric acid solution has molarity 357 μmol/L, what is the weight (in
milligrams) of uric acid in this solution? Mr (uric acid) = 168
[0.003 mg]
9. If 11.3 g NaCl is dissolved in 325 mL of water, what is the weight concentration
(g/L) and molarity (mol/L) of the solution?
Mr (NaCl) = 58.5, density of NaCl solution = 1 g/cm3
[33.6 g/L, c = 0.57 mol/L]
10. The patient excreted 1500 mL of urine per 24 hours. Chemical analysis shows
the urine creatinine mass of 2.625 g in 1500 mL of urine. Calculate the creatinine
molarity in mmol/L.
Mr (creatinine) = 113
[c = 15.5 mmol/L]
11. 1 liter of human blood plasma contains about 100 mmol Cl-. How many miligrams
of Cl- are found in 1 mL of plasma? Ar (Cl) = 35.5
[3.55 mg]
12. Calculate the weight of 0.9 % NaCl solution that contains 720 mg NaCl.
[80 g]
13. Calculate the mass (in grams) of pure ethanol in 0.5 dm3 of 40% solution (v/v).
Density of 100% ethanol equals 0.7893 g/cm3.
[157.86 g]
14. How many grams of AgNO3 are required for preparation 750 mL of 20 mM
solution? Mr (AgNO3) = 170
[2.55 g]
15. How many mililiters of 68% HNO3 are required for preparation 0.5 L of 1.0 M nitric
acid solution? Density 68% HNO3 = 1.4 g/mL, Mr (HNO3) = 63
[33.09 mL]
16. Calculate the volume of 70% HClO4 (in mL) you need for preparation of 0.5 L of
0.2 M HClO4. An information found on the bottle of the 70% HClO4 is followed:
density = 1.67 g/cm3, relative molar mass of HClO4 = 100.5
[8.6 mL]
17. A 2 M H2SO4 solution has density 1.1 g/cm3. What is the percent by mass of this
solution? Mr (H2SO4) = 98
[17.8 %]
18. What is the percent by mass concentration of a 2.81 M HNO 3 solution (density =
1.18 g/cm3)? Mr (HNO3) = 63
[15 %]
19. What is the molarity of 96 % H2SO4 solution? Density of H2SO4 solution is 1.86
g/cm3. Mr (H2SO4) = 98
[c = 18.22 mol/L]
20. Calculate the molarity of 15% HCl solution. Density of HCl solution is 1.047
g/cm3. Mr (HCl) = 36.5
[c = 4.3 mol/L]