In this experiment, the effect of concentration on rate of reaction was investigated. We did this by reacting marble chips (calcium carbonate) with hydrochloric acid,
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Introduction
Raw Data Time (s) [�0.5s] Loss in Mass (g) [�0.01g] 0.0 0.00 20.0 0.70 40.0 1.00 60.0 1.20 80.0 1.40 100.0 1.55 120.0 1.65 140.0 1.75 160.0 1.80 180.0 1.85 200.0 1.90 220.0 1.90 240.0 1.95 260.0 1.95 280.0 1.95 300.0 1.95 320.0 2.00 340.0 2.00 Time (s) Loss in Mass of Carbon Dioxide (g) Moles of CO2 (moles) Moles of HCl reacted (moles) Moles of HCl remaining (moles) Concentration of HCl remaining (moldm-3) 0 0.00 0.000 0.000 0.100 2.000 20 0.70 0.016 0.032 0.068 1.364 40 1.00 0.023 0.045 0.055 1.091 60 1.20 0.027 0.055 0.045 0.909 80 1.40 0.032 0.064 0.036 0.727 100 1.55 0.035 0.070 0.030 0.591 120 1.65 0.038 0.075 0.025 0.500 140 1.75 0.040 0.080 0.020 0.409 160 1.80 0.041 0.082 0.018 0.364 180 1.85 0.042 0.084 0.016 0.318 200 1.90 0.043 0.086 0.014 0.273 220 1.90 0.043 0.086 0.014 0.273 240 1.95 0.044 0.089 0.011 0.227 260 1.95 0.044 0.089 0.011 0.227 280 1.95 0.044 0.089 0.011 0.227 300 1.95 0.044 0.089 0.011 0.227 320 2.00 0.045 0.091 0.009 0.182 340 2.00 0.045 0.091 0.009 0.182 Analysis: 1. ...read more.
Middle
We did this by reacting marble chips (calcium carbonate) with hydrochloric acid, and recording the expelled mass loss of carbon dioxide as the concentration of hydrochloric acid began to drop. The carbon dioxide loss in mass over time was used to calculate the rate of reaction. In chemistry, the rate of reaction is used to describe how quickly a reaction happens. It is defined as the measure of the amount of reactants being converted into products per unit amount of time. In our case, we measured the amount of hydrochloric acid and calcium carbonate being converted into carbon dioxide in 20 seconds intervals. There are several ways to vary and experiment with a rate of reaction. Students can observe a change in volume of gas produced, change the transmission of light in the experiment, change the concentration using titration or even change the concentration using conductivity. For this experiment, we observed rate of reaction by a change of mass. We calculated our rate of reaction by dividing the grams of carbon dioxide released by 20 seconds. Because 20 seconds was a constant divisor, the more mass of carbon dioxide released, the greater the rate of reaction. ...read more.
Conclusion
Be very careful when removing the cotton to avoid any tearing. If a piece of cotton is accidently torn off, do not throw it away! Keep it and weigh it so that it is accounted for. Experiment was not performed until carbon dioxide stopped being expelled. The data was limited. Carbon dioxide was still being produced and there were still 0.091 moles of hydrochloric acid left when the experiment was stopped. Do not finish the experiment until there is no more carbon dioxide being expelled. This way, we get a better idea of the limits and possibilities of the reaction rate and how far it can go. Timer was not started the same time the marble was entered. Some marble could have been left inside the solution for a longer or shorter time than others. As a result, carbon dioxide values could be lower or higher than they should have been. The timer should be alert and there should be communication between the partners. The timer needs to begin once the marble chips are placed inside, and it needs to be removed right after twenty seconds. By maintain a steady time of twenty seconds, we can properly assess the reaction rates without adding another independent variable of time. ...read more.
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