Thanks! C. Graham\'s Law Graham found that the rate of diffusion of a gas is inv

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Thanks! C. Graham's Law Graham found that the rate of diffusion of a gas is inversely proportional to the square root of the molecular weight of the gas. When the diffusion rates of two gases are compared mathematically by forming them into a ratio, Graham's law results in the following mathematical forms: diffusion rate Amoecular weight B diffusion rate B molecular weight A Eq.8.6 or in an abbreviated form rate A MWs rate B VMWA Eq. 87) In each of these equations, A and B represent the two different gases. When a gas is allowed to move down a tube by diffusion, the rate of diffusion is equal to the distance the gas moves divided by the time it takes for the movement to occur. In this part of the experiment you will allow two gases to diffuse simultaneously in a glass tube. The design of the experiment will allow you to measure the distance each gas moves. Since the diffusion takes place simultaneously, the time of diffusion is the same for each gas. Under such conditions, Equation 8.7 may be written as follows: rate A distance A/timeMWs rate B distance B/time MW Eq. 88) Because the times are identical and cancel, Equation 8.8 becomes rate A distance A MWs rate B distance B MWA Eq.89) This form of Graham's law makes it possible to compare diffusion rates for two gases by simply measuring the distance each gas travels in a tube during a fixed diffusion time. The two gases you will allow to diffuse are hydrogen chloride (HC) and ammonia (NHs). Both of these gases are available in the laboratory as water solutions called hydrochloric acid and aqueous ammonia (or ammonium hydroxide). The respective gases readily escape from the concentrated solutions as evidenced by the strong odors of these When the two gases meet, a reaction occurs that produces finely divided white solid ammonium chloride. The reaction is: Eq. 8.10) It will be necessary to work in pairs on this part of the experiment. Procedure 1-Obtain a 50cm piece of dry glass tubing from the stockroom for each team.

Explanation / Answer

Molecular weight of HCl= 1+35=36amu

Molecular weight of NH3=14+3=17amu

HCl diffusion distance=|6.3-19.3| =13cm

NH3 diffusion distance=|6.3-0.4| =5.9cm

Experimental rate ratio= rate(NH3)/rate(HCl)= 5.9/13= 0.45

Theoretical rate ratio= (36/17) = 1.45

I think there is mistake in observation of plug locations. Because theoretical value cannot be wrong.

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