Sodium Thiosulphate and Hydrochloric Acid

Sodium Thiosulphate and Hydrochloric AcidAim To investigate how the ramble of reaction surrounded by Sodium Thiosulphate and Hydrochloric acid is affected by changing the tightness.BackgroundTHE REACTION when Sodium Thiosulphate reacts with hydrochloric acid sulphur is produced. The sulphur forms in very sm every particles and causes the solution to cloud over and turn a yellowish colour. This causes the underwrite to fade and eventu exclusivelyy disappear. Sodium Thiosulphate + Hydrochloric acid atomic number 16 + Sodium Chloride + Sulphur Dioxide + Water NA2S2O3 + 2HCL S + 2NaCl + SO2 + H2O (aq) + (aq) (s) + (aq) + (g) + (l) PREDICTION As the concentration of Sodium Thiosulphate profits the length of time for cross to disappear decreases (inverse). This is because the increase of concentration of Sodium Thiosulphate depart increase the mark of reaction between Hydrochloric acid and sodium Thiosulphate particles. SCIENTIFIC REASONS FOR PREDICTION the results from prelimi nary experiments support the prognostication made. From the results you can see that there is a directly proportional family relationship between the concentration and the charge per unit of reaction. If you increase the concentration then the sum up of reaction will as well increase.METHOD 1. Set up machine as in preliminary experiment. 2. Record the temperature of the room. 3. Add the first of the concentrations of sodium Thiosulphate to the flask. As you supplement 10cm3 of HCL and start the stopwatch 4. Watch the solution as it clouds over. Once the cross has disappeared stop the clock. 5. Record the time in a results table 6. retell the above steps for the other concentration of sodium Thiosulphate. Repeat the experiment 3 times for each(prenominal) of the concentrations. 7. Record all results in a table and work out the tell by dividing 1 by the average time for each.This extract was interpreted from the merge belowThis experiment is testing how the rate of reactio n is affected when concentration is changed. The theory is said that increasing the concentration can increase the rate of reaction by increasing the rate of molecular smashers. The phenomenon behind all of this is the collision theory and how it plays a big role in this investigation. The high the concentration the less time/faster it will take for the agreement to turn into equilibrium, and if concentration id decreased, time taken for the solution to go mirky increases.Hypothesis The higher the concentration the faster the rate of reaction will be and the time taken to reach equilibrium will decrease. A much reduce concentration will have a eternal rate of reaction and a longer time to reach equilibrium. setupMethod Gathered all the apparatus needed for the experiment. Using a weight balance we measure out 8g of Sodium thiosulphate, that we added too 200cm of pissing. We motley the solution until all the crystals were dissolved. Then you pour 50 cm, 40 cm, 30 cm, 20 cm, and 10 cm of the solution into five identical conical flasks. Then you add water to the other conical flasks so that the total volume in each flask in 50 cm. Make sure to estimate the flasks so you know which one has so much concentration. Once thats done, you must(prenominal) now take a beaker and add 35 cm of punishing Hydrochloric acid to 65 cm of water to make a diluted solution. Now take a piece of paper and draw a black cross on it, and then place one of the flasks on the paper (do one flask at a time). Using a measuring cylinder measure out 5 cm of the hydrochloric solution, and add this to the flask. Immediately stir the flask and start the stop watch. One person should do this part. As soon as you cant see the cross any more(prenominal) stop the stopwatch, and record the results in a table. Repeat this with all the flasks. ResultsConcentration (cm)Time (s)Rate of reaction (s)5024.90.0440 + water320.031330 + water42.20.023720 + water74.070.013510 + water202.80.0049The r ate of reaction is measured by dividing 1 by the time taken for the reaction to take place.Number of moles of sulphur utilize n= m/M n= 8/32 = 0.25 mols backchatYou can see from the graph that as concentration increases, the time taken for the solution to go cloudy decreases. So the stronger the concentration the faster the rate of reaction is. As the concentration of sodium Thiosulphate decrease the time taken for the cross to disappear increases, this is an inverse relationship.When equilibrium was reached the solutions turned a yellow color, the stronger the concentration was the higher the turbidity was. When equilibrium was reached SO2 gas and water were released. The more concentrated solution has more molecules, which more collision will occur. So therefore the rate of reaction should depend on how frequently the molecules collide, so more molecules have greater collisions and the reaction happens faster as more products are made in a shorter time. All related to the collisi on theory.What we saw what happened was exactly what we expected from the experiment. Our predictions were right.EvaluationThe method we used was plumb accurate, our results werent perfect but they were good enough for us to see what happens during the experiment. So overall the results proved the hypothesis and I was able to draw graphs with a line of best fit. In our experiment we keep the HCL a constant, and also keeping the volume of the solution was important to get more accurate results. The results were fairly reliable under our conditions. They could be a bit remove from bad measuring, unclean equipment and the timing. ConclusionWhen the concentration of Sodium thiosulphate was increased the rate of reaction increased and the time taken to reach equilibrium decreased, so therefore the rate of reaction is directly proportional to the concentration.Bibliographyazete.com/view/48253 6 September 2009 woodrow.org/teachers/ci/1986/exp19.html 9 September 2009