The Relationship between Molecular Weight and the Rate of Diffusion of Substance
Anthony Earl D. Cristobal
Group 1 Sec. U-7L
16 October 2014
Abstract
The relationship between the molecular weight and the diffusion of the substance was determined using two laboratory experiments. In the first experiment, a horizontally placed glass tube was set. Two cotton balls were soaked in hydrochloric acid (HCl) and ammonium hydroxide (NH3). At the same time, the cotton balls were inserted at both ends of the tube. Several seconds later, a white cloud formed where the gases of the substances met, but nearer to the side of the hydrochloric acid, which has heavier molecular weight than ammonium hydroxide. In the second experiment, a
…show more content…
A drop of potassium permanganate, potassium dichromate and methylene blue were introduced to those wells. Every three minutes the diameters those drops are measured and recorded for 30 minutes. Since methylene blue has the highest molecular weight (374g/mole) among the three solutions, methylene blue has the slowest rate of diffusion and has the shortest diameter.
Materials and Method
Glass Tube Experiment A glass tube was horizontally placed on an iron stand. Two cotton balls of identical size were soaked in hydrochloric acid and ammonium hydroxide and were plugged simultaneously to the separate ends of the tube. After several seconds, a white cloud inside the tube was observed and the measure from both ends to the cloud was recorded.
Agar-water gel Experiment A petri dish containing agar-water gel with three holes was given. Each of those wells are dropped with potassium permanganate (158 g/mole), potassium dichromate (294 g/mole) and methylene blue (374g/mole). The diameters of the three drops were recorded at a three minute interval for thirty
…show more content…
This also supports the hypothesis that molecular weight affects the rate of diffusion.
Table 5: Line graph of the diameters of the substances in a three minute interval for thirty minutes
Summary and Conclusion According to the experiments made and data gathered, the results strongly support the hypothesis. HCl, having the greater molecular weight, diffused slower than NH3, was closer to the white cloud formed inside the tube than the side of NH3. Potassium permanganate, which has the least molecular weight among the three substances in the agar-water experiment, obtained the largest diameter while the methylene blue, which has the largest molecular weight, got the shortest. Because of these experiments, we can therefore conclude that there is a relationship between the molecular weight and the rate of diffusion. They are inversely proportional. Therefore the higher the molecular weight, the slower the rate of
The serial 2-fold dilution were done with a volumetric pipette, its pump, and 10 mL volumetric flasks. Eight different solutions were produced, half of which came from Red 40 and the other half, from Blue 1. These different concentrated solutions were placed in a 10 mL volumetric flask, each labelled with either R for Red 40
Introduction The purpose of this Lab was to identify the density of the unidentified object and determine what substance the unidentified object given by the teacher was. The density calculated in the experiment will stay the same because the density of the unidentified object will stay constant. The Independent Variable of this experiment was the calculated density and the unidentified object given. The Dependant Variable for this experiment was the density.
Procedure and Observations To begin the lab, first all the correct equipment and materials had to be collected
These difficulties might have caused me to make mistakes on the amount needed to pipette or the type of substance. Overall, next time I would have made sure to pay closer attention to the pipetting portion of the procedure. Furthermore, we could extend this experiment by trying different kinds of
After 15-20 minutes, color separation became visible; red and blue were shown around the purple as well as blue/yellow around green. Solution line stopped at 60cm. Data and Observation The water/salt solution percolates faster than the alcohol/water solution. Alcohol & water solution:
Introduction The intent of this experiment is to understand how hot and cold water interact with each other by combining clear hot water and black ice cold water. I hope to learn more about how hot and cold water interact with each other. As of now, I know that cold water is denser than hot water. Knowing this I formed my hypothesis.
In our gummy bear lab experiment, we experienced osmosis, the water version of diffusion. My lab partner, Maggie, and I were given two yellow gummy bears. The first one measured at 10 mm in both thickness and width, and 21 mm in height. The approximate volume was 2,100 mm^3, and the mass was 2.567 grams. The second one was 11 mm in thickness, 9 mm in width, and 20 mm in height.
For this lab I will be using water and sucrose to demonstrate the rate of osmosis. In this lab I will be exploring how temperature impacts the rate of osmosis by placing pieces of potato of equal size in solutions of different temperatures and observing the change in mass of potato after a given period of time. The change in mass will indicate the rate of osmosis.
These small errors may be arised as a result of temperature. Because the accurate mesuring process took much time and during this time the temperature of water was decreasing. Among two methods the density bottle gives more accurate measurement of the volume, resulting in more accurate determination of density. One of disadvantages of hydrometer is that hydrometer has Operator dependent readings, therefore has limited accuracy. Morever, for measuring the density using hydrometer large sample volume is required.
The temperature of the sulphuric acid was not measured throughout the experiment, however the room in which the experiment was conducted was kept constant, so the chance of any large error due to unknown temperature of the sulphuric acid was most likely reduced. The amount of sulphuric acid used was also controlled by measuring 100mL with a 100mL measuring cylinder to ensure that the results would be consistent. The volume of the agar cubes was calculated from the surface area of each agar cube, both before and after they had been in the sulphuric acid. This increased the reliability of the results as it allowed the rate of diffusion of the sulphuric acid into the agar cubes to be calculated more accurately. The concentration of the acid was 0.1M, which was placed in all three agar cubes to maintain consistency of results.
In this practical agar jelly cubes will be used to represent a cell. AIM: To model diffusion in a practical form and investigate the effect of surface area to volume ratio. HYPOTHESIS: It is hypothesised the smaller the cube the quicker and bigger the rate of diffusion will be and with a larger cube there will be a smaller percentage of diffusion due to its bigger volume.
The size of the pore matters as well. Diffusion is when the movement of molecules from an area of high concentration to an low area concentration. Osmosis is the movement of water
Biology Design Practical Joshua Edwards What are effects of the volume of a potato and the amount of weight it loses when placed in salt solution? Introduction This design practical uses a potato’s surface area to volume ratio to see what affects it has on osmosis in different concentrations. Osmosis is the movement of water molecules through a cell membrane into an area of a higher solute concentration. The movement goes the way of the solvent with more solute because the lower solute concentration is drifting through balancing the ratio of solute per solvent (En.wikipedia.org, 2018).
The thinner the container the slower the reaction as there are less particles which the substances can collide with. Use the same sized container for every experiment
Therefore, this experimentation indicated that the sucrose molecules cannot diffuse from the concentration of the dilute solution, while on the other hand the water molecules diffuse from the dilute solution to the concentrated one. Hypothesis: If the (independent variable) sucrose of the dilute solution is