Mapúa Institute of Technology
School of Chemical Engineering, Chemistry, Biological Engineering and Materials Science Engineering
Determination of Radius of Glycerol Molecule by Viscosity
Romero. Von Joby M.
Javier, Danica U.
Lagamayo, Linear L.
Perile, Gracielle Anne
Professor, School of Chemical Engineering, Chemistry, Biological Engineering and Materials Science Engineering, Mapua Institute of Technology;
Author, Student, CHM170/A41 Physical Chemistry
Laboratory 1, Biological Engineering and Chemistry, Mapua Institute of Technology
Members, Student, CHM170/A41 Physical Chemistry Laboratory 1, Biological Engineering and Chemistry, Mapua
Institute of Technology
To determine the viscosity of glycerol at very small concentration
To determine the radius of assumed spherical molecule of glycerol through measuring its viscosity at various dilute
To compare the obtained radius with the estimated radius of the spherical molecule through physical data
Viscosity, Glycerol, molecular size, infinite dilution, limiting slope method
Viscosity is basically the measure of internal resistance of a
fluid to flow. This vital property of substances can be defined
as the fluid friction and is related to the capacity of individual
molecules on a certain fluid to move with respect to one
another. Thus, viscosity depends oh how each molecule is
attracted to one another. The strength of these attractions is
affected by the composition, size and shape, the kinetic energy
of the molecules, which is dependent on temperature, and the
intermolecular forces of the fluid.
Figure 1. Differential flow of two sheets, showing the velocity gradient and
the area of contact.
When two layers of fluid move past one another with a certain
velocity, both layers experience a force which tends to oppose
their relative motions. The magnitude of this force is dependent
on two factors, namely the area of the plane of contact
between the layers and the velocity gradient normal to it. This
scenario is similar to sliding of palm of one hand over the other.
Mathematically, the effect is expressed as:
where u is the velocity of the flow, du is the difference in
velocity between two fluid layers, dx is the difference in
position, normal to the flow, between two fluid layers and A is
the area of contact. By definition, F/A is termed as the “viscous
shear stress”, .
One method of determining viscosity is through the use of an