Concentration of HCL affecting surface area to vol ratio Essay Example for Free

minginess of HCL affecting out firmament to vol ratio EssayThe research question that this report is going to question is What is the relationship between compactness of hydrochloric astringent (HCl) and the identify of public exposure? My hypothesis for this research question is that turn in pass judgment of spreading will be observed when the agar-agar blocks are placed in upshots of distinct parsimoniousnesss of HCl. As the concentration of HCl increases, the rate of spreading will also increase due to the steep concentration gradient created.To investigate the change in rate of diffusion when different concentrations of HCl are used, I used agar blocks that are stained with universal indicator that would change from dark-green to pink when open(a) to HCl. To prepare the agar blocks, I used knife and ruler to acquire 5 agar blocks with satisfactory proportionalitys of 3. 0cm by 1. 0cm by 0. 5cm. Then I prepared 5 different concentrations of HCl with equa l volume of 5cm3 in test tubes, which were 0. 0M. 0. 2M, 0. 4M, 0. 6M, 0. 8M and finally 1. 0M of HCl.Then, I placed the agar blocks into respective test tubes, measuring the clock organizen for the agar blocks to turn from green to completely pink. This was repeated 2 to a largeer extent prison terms, having 3 site of readings in total. The results collected showed an increasing trend in the rate of diffusion as the concentration of HCl increased. This clear supported the hypothesis I derived at. (227 words) ? Content Page Abstract2 Content Page3 Introduction4 Research question4 dead reckoning4 Introduction (2)5 Literature look back5 Methodology6 Results8 Results (2)9 Discussion10Limitations11 Improvements11 Conclusion12 Bibliography13 ? Introduction Research question How does change in concentration of hydrochloric acid (HCl) affect the rate of diffusion through the agar blocks which contain starch stained with universal indicator, speckle keeping surrounding temperature, the climb up area to volume ratio of agar blocks used and the volume of solution to which the agar blocks were placed constant? Hypothesis Change in rate of diffusion will be observed when agar blocks are placed in solutions of different concentrations of HCl.As the concentration of HCl increases, the rate of diffusion will also increase due to the steeper concentration gradient created ? Introduction (2) Literature Review Diffusion is known as the net movement of particles from a region of high concentration to a region of lower concentration along the concentration gradient. There are few factors that affect the rate of diffusion, the time taken for both regions to have equal amount of particles. One of them is temperature.It is known that temperature has the greatest encumbrance on diffusion rates and is the easiest of the factors to change. Increasing the temperature increases the diffusion rate by adding energy to each particle. This is because particles with more(prenomi nal) energy can move to the region of lower concentration with more speed and more easily. Similarly, profound the temperature will lower the diffusion rate by lowering the energy of each particle. Another meaning(a) factor that changes the rate of diffusion is the concentration gradient, which we will be exploring in this experiment.The rate of diffusion depends on the difference between concentrations across the region of lower concentration and higher concentration, with steeper concentration differences resulting in higher diffusion rates (Simon 2013). This can be explained by Ficks Law, which can be summarised by this equation Rate of diffusion is proportional to(surface area x difference in concentration )/(Length of diffusion path). From the equation derived from Ficks Law, it is clearly seen that the difference in concentration (concentration gradient) will increase the rate of diffusion (Michael Kent 2000).This theory can be used to explain real life situations, like how human lungs take in type O and give out carbon dioxide in a split second. It is due to the great difference in concentrations of both gases (very steep concentration gradient) that allows relatively fast rate of diffusion. For instance, when breathing in, the concentration of oxygen in alveoli is very high compared to that in the blood vessels surrounding the alveoli. Thus, rate of diffusion is great, allowing oxygen to diffuse as fast as possible. (BBC 2013) Methodology plank 1.1-Table of variables and how it is controlled VariablesDetails of variablesHow it is controlled Independent VariableConcentration of HClConcentration of HCl is controlled by the amount of distilled piddle added to HCl. For example, in order to achieve a concentration of 0. 2 moldm(-3), 1. 0 cm3 of 1 mol of HCl is added, with 4 cm3 of distilled water added. Dependent VariableRate of Diffusion The time is taken by a stopwatch until the agar block turns pink in colour completely. Controlled VariableTemperatur e of the surrounding Surface area to volume ratio of the agar blocksVolume of solution to place the agar blocks into. Temperature is set at an air-condition room in a Biology lab The agar blocks are cut into resembling length, same breadth and same height (3. 0 cm by 1. 0 cm by 0. 5cm), thereof having the same volume and surface area. This ensures the ratio is the same. The volume of solutions used is kept the same at 5. 0cm3. Table 1. 2-Apparatus used in the experiment Apparatus QuantityUncertainty 2% Starch Agar (Universal Indicator stained) 1. 0 M Hydrochloric Acid (aq) Deionized Water Stop Watch20. 01sThis power be due to the in sinless cutting of the dimension of the agar blocks. It could also be due to our inability to decide whether the agar blocks have turned completely green to pink in colour. Thus, the calculated rate of diffusion could have changed. Limitations many(prenominal) of the results were not as accurate as it was difficult to see whether the agar blocks have turned altogether pink in colour. Some of the agar blocks still had strips of green in them when we removed it from the solution and cut it. This could have affected the time taken for the agar blocks to turn entirely pink and thus, affecting the rate of diffusion.The temperature of the solutions containing the agar blocks might not be constant throughout the whole experiment. This can be due to holding of test tubes with our transfer and also putting it down again several times. The heat from the hand might get transferred and the temperature might be altered. This can affect the time taken for the agar blocks to turn completely pink, as higher temperature induce faster rate of diffusion. Some of the results are not very accurate as the surface area to volume ratio was not constant for all the agar blocks tested.One of the reasons is due to the limit amount of agar blocks that were allocated for each bench. Another reason is that it was difficult to use the knife provided to cu t the agar blocks in a straight manner and as accurately. This limitation can affect the time taken for agar blocks to turn pink, followed by the rate of diffusion, as some blocks are bigger while some are smaller than the others. Improvements In order to make sure that the agar blocks have turned entirely pink, use a light and put it in a white background where the colour changed is more visible.Then, the calculated rate of diffusion will not be affected. Place the test tubes in a water bath where the temperature can be kept constant at the temperature of tap water. This way, the calculated rate of diffusion will not be affected. Lastly, use a stamp with all the desirable dimension of the agar blocks measured. This way, not only is it convenient, it also helps us acquire the accurate dimensions of the agar blocks, having the same surface area to volume ratio for all the agar blocks. Then, the calculated rate of diffusion will not be affected. ConclusionIn conclusion, the readings a nd the derived results in the form of tables, and line graph support my hypothesis, which is Change in rate of diffusion will be observed when agar blocks are placed in solutions of different concentrations of HCl. As the concentration of HCl increases, the rate of diffusion will also increase due to the steeper concentration gradient created. With the derived conclusion, it shows that in order for rate of diffusion to be greater, higher concentration of the solution mustiness be used, so that the concentration gradient is steeper.