Chemistry for Physiology
A bag containing 1 L of prepared intravenous saline solution is printed with “isotonic approximate osmolality 300 mOsm”. What is meant by osmolality?
It is the number of osmoles dissolved in kilogram of water.
It is the number of osmoles dissolved per litre of saline solution.
Osmolality is an alternate spelling for osmolarity, the number of osmole per litre of solution.
Osmolality is used for covalent solutes, while osmolarity is used for ionic solutes.
It is the number of osmoles dissolved in kilogram of water.
As osmolality (osmol/kg) refers to the concentration within a mass (a kilogram) of solution it is unaffected by the temperature of the solution. Osmolarity (with an “r”) in osmol/L refers to the concentration within a volume of a litre of solution. For human physiological solutions which are relatively dilute, there is virtually no difference between the concentrations of solutions when expressed as osmolarity or osmolality.
It is the number of osmoles dissolved in kilogram of water. As osmolality (osmol/kg) refers to the concentration within a mass (a kilogram) of solution it is unaffected by the temperature of the solution. Osmolarity (with an “r”) in osmol/L refers to the concentration within a volume of a litre of solution. For human physiological solutions which are relatively dilute, there is virtually no difference between the concentrations of solutions when expressed as osmolarity or osmolality.
Related posts
If a patient has blood pH that is 7.3 (which is below the healthy range of blood pH values), which of the following is a correct statement?A. The patient has alkalosis.
B. The patient has excessive alkali.
C. The patient has acidosis.
D. The patient has insufficient acid.
Choose the INCORRECT statement about buffer solutions.
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
Leave a Reply