Practical investigations
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I am currently on the evaluation section of my A2 investigation of metal and acid reaction. I've got anomalous results plotted on a graph of ln(rate) and 1/temperature, where my lowest temperature gave a very low ln(rate) compared to the rest.
What comments could I make on this? I have already stated some limitations which may have affected this.
I also have an anomalous plot on the graph of temperature vs rate of reaction, where the two points to not fit the exponential curve. I'm not quite sure how to comment this also.
090109
Corrie writes .....
It is a little surpising that your lowest temperature reading (room temperature?) is anomalous. How reliable is it - did you repeat it more than once? You could ignore it when drawing your straight line (making a comment to that effect) or try and draw two straight lines, one including it and one without, then work out two Ea values from the two slopes and compare the two in your write up, and with the many values reported by other students on this site (look under the Practical Investigations link on the Re:act Homepage).
If you are doing the standard ln(rate) vs 1/T Arrhenius plot to find Ea, then I can't see why you need a rate vs temperature plot as well??
Hope this helps? If not come back to us via Re:act, not email. You might find our tutorials on metal + acid reactions and our Sorted FAQs on Investigations useful - both can be found via the Practical Investigations link on the Re;act Homepage.
Risk assessment
Before attempting any practical work based on the advice and suggestions on this website, you must do the following. Identify any hazards, assess the risks from these hazards, and then decide appropriate control measures to reduce the risks. You must have these approved by those in authority in your school or college laboratory. Do not rely on what is said on this website.
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updated: 11 January 2009
