Osmolarity (Osm) is the molar concentration of the particles-molecules and/or ions-in a solution. In physiological solutions, 5 \% ({\rm m/v}) glucose ({\rm C}_{6}{\rm H}_{12}{\rm O}_{6}) and 0.9 \% ({\rm m/v}) {\rm NaCl}, the osmolarity must be the same as for the blood, which is 0.3 {\rm Osm}
1.Calculate the osmolarity of glucose in the solution.
2.Calculate the osmolarity of {\rm NaCl} in the solution.
Are these two solutions?
5% glucose is 50g/L = 50/180/L = 0.277 Osmolar.
0.9% NaCl is 9 g/L = 9/58.5/L = 0.15 and that times 2 = 0.308 Osmolar.
Thank you
To calculate the osmolarity of glucose and NaCl in the solution, we need to first determine their individual concentrations in terms of molar concentration.
1. Osmolarity of Glucose:
The given solution contains 5% (m/v) glucose. To calculate the molar concentration, we need to convert this mass/volume percentage to molarity.
a. Find the molar mass of glucose (C6H12O6):
- C = 6 x atomic mass of carbon
- H = 12 x atomic mass of hydrogen
- O = 6 x atomic mass of oxygen
Adding them up: 6(12) + 12(1) + 6(16) = 180 g/mol
b. Calculate the molarity of glucose:
We know that 5% (m/v) glucose means 5 g of glucose in 100 mL of the solution.
- Convert the volume to liters: 100 mL = 0.1 L
- Calculate the number of moles of glucose: 5 g / 180 g/mol = 0.0278 mol
- Divide the number of moles by the volume in liters: 0.0278 mol / 0.1 L = 0.278 M
Therefore, the osmolarity of glucose in the solution is 0.278 Osm.
2. Osmolarity of NaCl:
The given solution contains 0.9% (m/v) NaCl. Following the same steps as above, we can calculate the molar concentration.
a. Find the molar mass of NaCl:
- Na = atomic mass of sodium
- Cl = atomic mass of chlorine
Adding them up: atomic mass of sodium + atomic mass of chlorine = 23 + 35.5 = 58.5 g/mol
b. Calculate the molarity of NaCl:
We know that 0.9% (m/v) NaCl means 0.9 g of NaCl in 100 mL of the solution.
- Convert the volume to liters: 100 mL = 0.1 L
- Calculate the number of moles of NaCl: 0.9 g / 58.5 g/mol = 0.0154 mol
- Divide the number of moles by the volume in liters: 0.0154 mol / 0.1 L = 0.154 M
Therefore, the osmolarity of NaCl in the solution is 0.154 Osm.