ABSTRACT
The effect of molecular weight to the rate of diffusion of some substances was determined using two experiments that require glass tube and petri dish of agar-water gel with three wells. In the first experiment, two cottons were soaked in hydrochloric acid (HCl) and ammonium hydroxide (NH_4OH), respectively and were placed at the both ends of a glass tube simultaneously. The second experiment involved three wells filled with a drop of potassium permanganate (KMnO_4), potassium dichromate (K_2 Cr_2 O_7), and methylene blue, respectively. At a regular three-minute interval starting from zero minute to thirty minutes, the diameter (mm) of the colored area of the three substances was observed and recorded. The partial rates of diffusion
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Molar mass of any substance is the mass (in grams) of 1 mol of the substance and is acquired by adding the masses of the component atoms (Zumadhal, 2000).
Examples of some molar mass of known substances are one mole of ethylene has a mass of 28.0g, one mole of hydrochloric acid has a mass of 36.5g and one mole of sodium chloride has a mass of 58.5g (McMurry and Fay, 2004).
Diffusion and effusion rates are dependent on the speed of the molecules of substances. The slower the molecules move, the slower the chances of escaping a hole (in terms of effusion). At the same temperature, those molecules with higher molar mass have faster rate of diffusion (Atkins and Beran, 1992).
This study, conducted at Room C-127 of the Institute of Biological Sciences, University of the Philippines Los Banos, aimed to determine the effect of molecular weight to the rate of diffusion of some substances using a petri dish of agar-water gel with three wells. The specific objectives were
to determine the effect of the molecular weight to the distance covered by the substances at a given intervals of time; to present the gathered data using tables and graphs;
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The first experiment was done by using the substances hydrochloric acid (HCl) which has a molecular weight of 36.46 g/mole and ammonium hydroxide (NH_4OH) which has a molecular weight of 35. 04 g/mole. Using the first data acquired, it can be observed that ammonium hydroxide has more distance traveled than hydrochloric acid because of its smaller molecular weight.
The second experiment was done by using the substances potassium permanganate (KMnO_4), potassium dichromate (K_2 Cr_2 O_7), and methylene blue having a partial diffusion rates of 0.36 mm/min, 0.33 mm/min and 0.33 mm/min, respectively which means potassium permanganate which has a molecular weight of 158 g/mole, has covered more in terms of diameter than potassium dichromate and methylene blue which have a larger molecular weight.
After series of experiments and gathering and interpreting data, the results agree with the hypothesis: If the molecular weight is smaller, then the diffusion rate is faster.
LITERATURE CITED
Bayquen, A.V. 2013. Chemistry: Exploring Life through Science. 2nd ed. Quezon City: Phoenix Publishing House. p.
Investigating the Effect of Concentration on the Rate of Diffusion Aim: To find out if concentration affects the rate of diffusion. Prediction: I predict that the higher the concentration of acid the faster the reaction will be. Hypothesis: Diffusion is the spreading out of a gas or liquid from an area of low concentration to another area where it has a lower concentration until the overall concentrations are balanced. The Hydrochloric acid (HCl) diffuses into the gelatine cube of which contains Sodium Hydroxide (NaOH), which is an alkali. When the Hydrochloric acid combines with the Sodium Hydroxide they form salt and water, which is neutral therefore turning the pink cube to clear.
The Effect of Solute Concentration on the Rate of Osmosis Aim: To test and observe how the concentration gradient between a potato and water & sugar solution will affect the rate of osmosis. Introduction: Osmosis is defined as, diffusion, or net movement, of free water molecules from high to low concentration through a semi-permeable membrane. When a substance, such as sugar (which we will be using in the experiment we are about to analyse), dissolves in water, it attracts free water molecules to itself, and in doing so, stops them from moving freely. The effect of this, is that the concentration of (free) water molecules in that environment goes down. There are less free water molecules, and therefore less water molecules to pass across a semi-permeable membrane, through which sugar molecules and other molecules attached to them are too big to diffuse across with ease.
This cell membrane plays an important part in Diffusion. Cell membrane and Diffusion Diffusion is the movement of the molecules of gas or liquids from a higher concentrated region to a lower concentration through the partially permeable cell membrane along a concentraion gradient. This explanation is in the diagram shown below: [IMAGE] Turgor When a plant cell is placed in a dilute solution or a less concentrated solution then the water particles pass through the partially permeable membrane and fill the cell up with water. The cell then becomes Turgor or hard. An example of this is a strong well-watered plant.
The side of the membrane that has the higher concentration is said to have the concentration gradient. It drives diffusion because substances always move down their concentration gradient. The pressure gradient also plays a role in diffusion. Where this is a pressure gradient there is motion of molecules. The pressure gradient is a difference in pressure between two different points.
... while weighing the reactants would try and avoid letting the reagents get in contact with apparatus that may not be necessary so as to avoid loss of some the substance and this way the exact mass would be achieved.
Investigate the Osmosis of Potato Cells in Various Salt Solutions. Introduction I have been asked to investigate the effect of changing the concentration of a solution on the movement of water into and out of potato cells. I will be able to change the input of my experiment. The input variable is the concentration of the solution.
The Importance of Diffusion to Living Organisms Diffusion is basically the movement of chemical species (ions or molecules) under the influence of concentration difference. The species will move from the high concentration area to the low concentration area till the concentration is consistent in the whole system. Diffusion mostly occurs in gases and liquids as these can move freely. The main features of an efficient diffusion system would be that it has a large surface area, thin membrane and a continuous supply of substances. A large surface area is needed so that high amount of substances can be exchanged at a time while the thin membrane means that the diffusion pathway would be short so that it is more efficient.
To investigate the osmotic effect of changing the concentration of sucrose solution; distilled water, 20% sucrose solution, 40% sucrose solution, 60% sucrose solution on the change in mass of potato cylinder after 30 minutes of being in solution.
The same procedure was done using 10ml of CV and 20ml of sodium hydroxide, both separately diluted to 50ml and added in a large beaker. The absorbance was recorded. In the last trial, 10ml of CV, 10ml of NaOH were diluted to 50ml. Before adding the two mixtures, 1ml of soap was added to the NaOH solution and then poured into a large beaker, along with the CV. Absorbance was recorded and the materials
One of the best methods for determining mass in chemistry is gravimetric analysis (Lab Handout). It is essentially using the the mass of the product to figure out the original mass that we are looking for. Thus the purpose of our experiment was to compare the final mass in our reaction to the initial mass and determine the change in mass.
Levy, Joel. The Bedside Book Of Chemistry. Vol. 1. Millers Point: Pier 9, 2011. 34-84. 1 vols. Print.
According to the results shown, 2 M hydrochloric acid that was more concentrated had a faster rate of reaction than less concentrated 0.5 M hydrochloric acid. As could be seen from Figure 1: processed data, 2 M hydrochloric acid’s average water displacement of 9.1 cm was much larger than 0.5 M hydrochloric acid’s water displacement of 0.3 cm. Therefore, the trend of the reaction rate increasing as the concentration increased was shown. The hypothesis was supported by the evidence obtained from this experiment.
Looking at the table of results above and the graph, it is shown that the higher the temperature got, the shorter the reaction time. The obtained results have been plotted on a line graph of the temperature of hydrochloric acid (y-axis) against reaction time (x-axis). This line graph in fig.2 also clearly shows that as the temperature increases, so does the speed of the reaction, shown by a reduction in the time taken. This corroborates the collision theory, where as the temperature of particles increase, the particles gain more kinetic energy and react with each other upon collision. This is shown as to happen in the hydrochloric acid, where the hydrochloric acid particles collide more with the particles of the magnesium ribbon as the temperature was increased. The above graph shows a gradual sloping curve, which gets steeper at higher temperatures. This shows that the reaction will reach a peak rate of activity as the gaps between the temperature and reaction times continue to decrease. The experiment fulfills the aim and clearly shows that as the temperature of a reaction is increased so does it’s rate of reaction, proving the hypothesis to be correct.
The variation of ultrasonic velocity with concentration shows that interaction between solute and solvent. Ultrasonic propagation parameter yields valuable information regarding the behavior of liquid system, because intermolecular and intra-molecular association, dipolar interactions, complex formation and related structure changes affect the compressibility of liquid which produces variation in ultrasonic velocity.(S.C Bhatt applied phy...
The Effect of Salt Solution Concentration On The Mass Of Potatoes Introduction = == == == ==