Lab Report Gas Diffusion
S5E1 Gaseous Diffusion
1.0 ABSTRACT
In this experiment, our objective is to find out the gas diffusion coefficient, D of acetone in the air. This experiment is conducted at a temperature of 50ºC and atmospheric pressure. The method that is applied to conduct this experiment is called the Winkleman method where the level of acetone (Z) is determined every 15 minutes by using a microscope. With the level of acetone being determined, a graph of t/L+Lo (min /mm) vs. L-Lo (mm) is plotted and the gradient s of the graph is being calculated. With the gradient of the graph s, we calculated the diffusion coefficient, D of the experiment by applying Fick’s Law with mathematical derivation. From the experiment, the diffusion coefficient, D is 0.83 x 10-5 m2/s. Several errors are made in this experiment which causes the value of diffusion coefficient to deviate from the handbook value which will be discussed later.
Keywords: Acetone, Diffusion Coefficient, Fick’s Law, Temperature, Pressure
2.0 INTRODUCTION
The transport of one constituent from region of higher concentration to that of a lower concentration is called mass transfer. A lump of sugar added to a cup of black coffee eventually dissolves and then diffuses uniformly throughout the coffee. Perfume presents a pleasant fragrance which is imparted throughout the surrounding atmosphere. These are examples of mass transfer. Mass transfer plays a very important role in many industrial processes: the removal of pollutants from plant discharge streams by absorption, the stripping of gases from wastewater, neutron diffusion within nuclear reactors, the diffusion of adsorbed substances within the pores of activated carbon, the rate of catalyzed chemical and biological reactions, and air conditioning are typical examples.
. Mass transfer takes place in either gas phase or liquid phase or in both cases simultaneously. When a liquid evaporates into a still gas, vapour is transferred from the surface to
1.0 ABSTRACT
In this experiment, our objective is to find out the gas diffusion coefficient, D of acetone in the air. This experiment is conducted at a temperature of 50ºC and atmospheric pressure. The method that is applied to conduct this experiment is called the Winkleman method where the level of acetone (Z) is determined every 15 minutes by using a microscope. With the level of acetone being determined, a graph of t/L+Lo (min /mm) vs. L-Lo (mm) is plotted and the gradient s of the graph is being calculated. With the gradient of the graph s, we calculated the diffusion coefficient, D of the experiment by applying Fick’s Law with mathematical derivation. From the experiment, the diffusion coefficient, D is 0.83 x 10-5 m2/s. Several errors are made in this experiment which causes the value of diffusion coefficient to deviate from the handbook value which will be discussed later.
Keywords: Acetone, Diffusion Coefficient, Fick’s Law, Temperature, Pressure
2.0 INTRODUCTION
The transport of one constituent from region of higher concentration to that of a lower concentration is called mass transfer. A lump of sugar added to a cup of black coffee eventually dissolves and then diffuses uniformly throughout the coffee. Perfume presents a pleasant fragrance which is imparted throughout the surrounding atmosphere. These are examples of mass transfer. Mass transfer plays a very important role in many industrial processes: the removal of pollutants from plant discharge streams by absorption, the stripping of gases from wastewater, neutron diffusion within nuclear reactors, the diffusion of adsorbed substances within the pores of activated carbon, the rate of catalyzed chemical and biological reactions, and air conditioning are typical examples.
. Mass transfer takes place in either gas phase or liquid phase or in both cases simultaneously. When a liquid evaporates into a still gas, vapour is transferred from the surface to
References: ❖ Brodkey, R. S. & Hershey, H. C. (1998), Transport Phenomena: A Unified Approach, McGraw-Hill. ❖ Welty, J. R. & Wicks, C. E. (1984), Fundamentals of Momentum, Heat and Mass Transfer, J. Wiley. ❖ Christie J. Geankoplis (1993), Transport Processes and Unit Operations (3rded.), Prentice Hall International Inc. ❖ H. P. Skelland (1974), Diffusional Mass Transfer, J. Wiley & Sons Inc. ❖ Felder, R.M. & Rousseau, R.W. (2000), Elementary Principles of Chemical Processes (3rd ed.), J. Wiley & Sons, Inc.