Minimizing chances for experimental error was huge. When we do this experiment, it may be necessary to wear safety goggles, as things are very unpredictable, and even though it is very unlikely that the solution would come out of the beaker during the experiment, one must still be cautious of spills. Perform this demonstration in a well-ventilated lab only. Add 2 ml of zinc iodide starch solution and titrate from blue to colorless. I will now give a simple definition of what rate of reaction actually is.
Then repeat steps a - g again using 15cm3 instead of 10cm3 of hydrochloric acid. In solution the particles are constantly moving. The method was made reliable by: — Labelling all equipment to prevent contamination. Method Firstly, we drew a black cross on a white piece of paper. Consult the teacher of any injuries or accidents. Once in 2008 3 and once in 2016 5.
Background information The collision theory briefly: For a reaction to occur particles have to collide with each other. The time taken for this to happen is the measure of the rate of reaction. By referring to this graph it can be observed that the equivalence point is roughly at 7. Materials required to perform this activity are available in the Reaction Order and Rate Laws—Student Laboratory Kit available from Flinn Scientific. This is new to me and I have not seen it before. How should we go about changing this? From this I can determine that, if there is an increase in the concentration of hydrochloric acid, then the time may be affect, as it will decrease and be lower, therefore disturbing my results. Sodium thiosulfate is safe to handle and store, but if it is mixed with an acid, a reaction happens.
The rate is directly proportional to concentration, and the reaction appears to be first order with respect to sodium thiosulfate concentration. The minimum energy that a particle must have to overcome the barrier is called the activation energy, or Ea. The total volume of each solution should be the same in each beaker. Two 50cm3 and two 10cm3 measuring cylinder. Please tell you've got it or you know what i'm on about? The reaction that will be taking place will follow the rate at which sulphur is formed in the reaction of sodium thiosulphate with dilute hydrochloric acid.
Sources of Error For the first experiment I used a small 100cm3 conical flask, this was hard to pour into as the opening was narrower, therefore when pouring the hydrochloric acid, I had to pour slowly, which may have effected the results as I was timing, the experiment. I have chosen to investigate the effect temperature and concentration have on a reaction. This affects the integration, and therefore the integrated rate law, just as Kaleb says. Introduction: Chemistry happens everywhere, not just in a lab. Coursework about sodium thiosulphate and hydrochloric acid. The reaction will continue and eventually the solutionwill turn completely opaque. By referring to table one and two, we can see the recorded pH changes when hydrochloric acid and sodium hydroxide were added respectively.
Another thing we could have done to bring more evidence is to have tried to use the Hydrochloric acid as the variable substance, and used the Sodium Thiosulphate as the constant substance. We had to add the Sodium Thiosulphate and the water at the same time for this to be a fair test also. Introduction: This experiment will be carried out by drawing a cross on a piece of paper and mixing hydrochloric acid and sodium thiosulphate together to see if the cross disappears. Also, we need to wash the beakers and cylinders before using them as there could be another chemical left in the bottom. If you start the time at different times, the experiment will be unfair and the results will be inaccurate. Reveal answer down Different people may decide that they cannot see the cross at different amounts of cloudiness, leading to errors in deciding when to take the reaction time.
We then emptied out the contents of the beaker, cleaned it out and dried it out. Each of these tangents has a gradient which is the rate of the reaction at that concentration. Then pour all of the contents into conical flask. Prediction I predict that as I decrease the concentration of the hydrochloric acid, the reaction rate will get slower. This can be easily done by measuring the time taken t for forming a certain amount of sulphur. The reaction time is more difficult to measure at lower concentrations because the onset of turbidity is more gradual.
Before the reaction starts, the mark is clearly visible from the top of the conical flask through the solution. How to control variables that could affect my results. How does temperature affect the rate of reaction between hypo and dilute hydrochloric acid? This solid precipitate clouds the solution, preventing the experimenter from seeing through the reaction vessel. A school lab does not have enough sophisticated equipment which will allow us to measure the concentration of a reactant after a given period of time when the reaction is still continuing. This reaction is a neutralization reaction, where phenolphthalein, a weak acid, reacts with a strong base, sodium hydroxide. The time taken t for the mark to totally disappear indicates how fast the reaction has occurred.