The Effect of Molecular Weight on the Rate of Diffusion of Potassium Permanganate (Kmno4), Potassium Dichromate (K2Cr2O7) and Methylene Blue ¹
The Effect of Molecular Weight on the Rate of Diffusion of Potassium permanganate (KMNO4), Potassium dichromate (K2Cr2O7) and Methylene blue ¹
ABSTRACT
The effect of molecular weight on the rate of diffusion was determined using the Agar-water Gel Test. One drop of potassium permanganate (KMNO4), potassium dichromate (K2Cr2O7) and methylene blue were used. Each substance has a respective molecular weight of 158 g/mol, 294g/mol and 374 g/mol. The diameters (in millimeter) were measured over time and the partial rates were computed. Results showed that as the time elapsed increases, the rate of diffusion decreases and the substance with the lowest molecular weight had the highest diffusion. Thus, the rate of diffusion of diffusion is inversely proportional with time and molecular weight.
INTRODUCTION
Diffusion is the movement of molecules, atoms or ions of a substance across a membrane from a region of high concentration to a region of low concentration in a medium. The movement in diffusion is a net movement where any given particle could move in any direction at any particular time until equilibrium is reached (Morgan et al., 1969). At equilibrium, molecules continue to move back and forth but the net change on either sides of the membrane is zero because the particles are distributed evenly (Campbell et al., 2006). According to Sherman and Sherman (1989), the different rates of diffusion of a substance is due to the inherent heat energy of the molecules proportional dependent to temperature, electrical charges and arrangement of atoms or molecules, pressure, and molecular weight.
Past experiments using a glass tube and cotton balls moistened with hydrochloric acid (HCl) and ammonium hydroxide (NH4OH) showed that the rate of diffusion of each substance is dependent on their molecular weight. Furthermore, a hypothesis was formulated that if the molecular weight affects the rate of diffusion of substances, then a higher molecular
ABSTRACT
The effect of molecular weight on the rate of diffusion was determined using the Agar-water Gel Test. One drop of potassium permanganate (KMNO4), potassium dichromate (K2Cr2O7) and methylene blue were used. Each substance has a respective molecular weight of 158 g/mol, 294g/mol and 374 g/mol. The diameters (in millimeter) were measured over time and the partial rates were computed. Results showed that as the time elapsed increases, the rate of diffusion decreases and the substance with the lowest molecular weight had the highest diffusion. Thus, the rate of diffusion of diffusion is inversely proportional with time and molecular weight.
INTRODUCTION
Diffusion is the movement of molecules, atoms or ions of a substance across a membrane from a region of high concentration to a region of low concentration in a medium. The movement in diffusion is a net movement where any given particle could move in any direction at any particular time until equilibrium is reached (Morgan et al., 1969). At equilibrium, molecules continue to move back and forth but the net change on either sides of the membrane is zero because the particles are distributed evenly (Campbell et al., 2006). According to Sherman and Sherman (1989), the different rates of diffusion of a substance is due to the inherent heat energy of the molecules proportional dependent to temperature, electrical charges and arrangement of atoms or molecules, pressure, and molecular weight.
Past experiments using a glass tube and cotton balls moistened with hydrochloric acid (HCl) and ammonium hydroxide (NH4OH) showed that the rate of diffusion of each substance is dependent on their molecular weight. Furthermore, a hypothesis was formulated that if the molecular weight affects the rate of diffusion of substances, then a higher molecular
Cited: Campbell, N.A., et al. 2006. Biology: Concepts and Connections. 5th ed. Philippines: Pearson Education South Asia PTE. LTD. p. 81 Dickson, T.R. 1987. Introduction to Chemistry. 5th ed. Canada: John Wiley & Sons, Inc. p. 320 Morgan, D., et al. 1969. Biological Science: The Web of Life. Australia: Simmon Limited. p. 134 Sherman, I.W. and V.G. Sherman. 1989. Biology: A Human Approach. 4th ed. New York: Oxford University Press, Inc. p. 31