Rates of reaction - concentration Essay Example for Free

Rates of reaction concentration Essay This experiment tests how differing concentrations affect the rate of a chemical reaction. It will be done using a simple experiment where one substance is constant and the other is varying. Apparatus For each experiment I will need the following; 150 cm3 2 Molar hydrochloric acid 140 cm3 water 250 cm3 sodium thiosulphate 1 conical flask 1 measuring cylinder 1 stop clock 5 pieces of paper 1 pen Preliminary Work; Prior to this investigation, I conducted a preliminary experiment to determine the strength of my method in terms of accuracy and precision. I decided to test how the temperature of an experiment affects the rate of reaction. Therefore, I got 50 cm3 sodium thiosulphate and 40cm3 hydrochloric acid diluted with 10cm3 water. After pouring the two mixtures into a conical flask I placed it onto a black cross on a piece of paper and timed the time it took for the precipitate of sulphur produced to make the solution seem so cloudy the cross disappeared. The same experiment was conducted at temperature of 10Â °C, 20Â °C, 30Â °C, 40Â °C and 50Â °C. The two substances that I have chosen for preliminary work will give me an accurate indication of the time taken for the reaction to occur in the actual investigation, as unlike with most experiments, the chemicals produce the precipitate of sulphur which turns the solution a milky yellow colour which is easy to see clearly. From my previous work, I can see that the range of temperatures was enough to give a clear summary of the investigation; therefore, I am transferring the range of temperature to use as amounts of hydrochloric acid as I feel it gives reliable results. Method After retrieving all the apparatus that is needed to successfully complete the experiment, I will begin with drawing a large cross onto the piece of paper. Then I will measure out five different quantities of both water and hydrochloric acid using a measuring cylinder in the following Display complete essay The above preview is unformatted text This student written piece of work is one of many that can be found in our GCSE Patterns of Behaviour section.