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Introduction

The Effect of the Particle Size on the Rate of Reaction CaCO3 (s) + 2HCl(aq) --> H2O (l) + CO2 (g) + CaCl(aq) Variables: Variable Methods of Measurement Independent Size and Surface area of the CaCO3 particle; in chip of approximately 3x3x3 mm in size or in powder form. Pre-measured. Materials are given. Dependent Volume of gas produced in 3 minutes measured by the graduated glass collecting tube Using a graduated glass collecting tube. The gas produced will push the water out of the tube and the volume of gas can be read on the tube Controlled Variables: Variables Why it must be controlled? How could it impact the results? How it will be controlled Condition of where the CaCO3 and HCl are kept Different conditions of the CaCO3 will result in different inaccurate measurement when the experiment is carry out, some CaCO3 might have been kept at different temperature, which would alter the amount of energy they have, thus changing their collision potential with HCl molecules Both the powder and the chip CaCO3 and HCl solution must be kept in the same condition and temperature to ensure that throughout the experiment, they have consistent energy and collision potential Molarity of HCl This different amount of HCl liquid will cause the glass production to varies if were to used the different volume of HCl Use 8ml of 2M HCl in every ...read more.

Middle

CO2 produced from the reaction between 0.6 g of CaCO3 powder and 8 ml of 2M HCl over 3 trials and the mean, in intervals of every 10 seconds. The uncertainty is 0.05 ml as the readings are analog and the smallest unit is 0.1 ml Time/s Volume of CO2 produced /ml (�0.05) Volume of CO2 produced /ml (�0.05) Trial 1 /ml (�0.05) Trial 1 /ml (�0.05) Trial 1 /ml (�0.05) 0 0.0 0.0 0.0 0.0 10 22.0 17.0 12.0 17.0 20 32.0 17.0 21.5 23.5 30 35.0 35.0 27.0 32.3 40 39.0 42.0 31.5 37.5 50 41.0 43.0 34.5 39.5 60 42.0 44.0 37.0 41.0 70 43.0 45.0 39.5 42.5 80 43.0 46.0 41.5 43.5 90 44.0 47.0 44.5 45.2 100 44.0 47.0 46.5 45.8 110 45.0 47.0 48.0 46.7 120 46.0 47.0 49.5 47.5 130 46.0 47.0 49.5 47.5 140 46.0 48.0 49.5 47.8 150 46.0 48.0 49.5 47.8 160 46.0 48.0 49.5 47.8 170 46.0 48.0 50.0 48.0 180 46.0 49.0 50.0 48.3 Analysis Figure 1: Amount of CO2 released from the reaction between HCl and CaCO3 Powder-a scatter graph of raw data collected over 3 trials showing volume of CO2 as the independent variable and how it changes over a period of 180 second. Error Bars represent uncertainty(�0.05 mL) ...read more.

Conclusion

The CO2 gas needed to build up enough pressure to overcome the water in order to go through. This causes the gas to travel inconsistently, and making the result inconsistent as well. This could be solved by changing the direction of the tube and using a shorter tube. Another cause for loss of gas is the inability to capture the gas immediately as the reaction starts. As soon as HCl is poured into the flask with CaCO3, the reaction starts and produces CO2, water, and CaCl, however, the flask has to be opened in order to transfer the solution, and some gas may be lost in that opening. This is very important as the beginning section is where the rate of reaction is the greatest. This can be solved by using teabags or other similar methods to separate the reactants without exposing them to the environment. Another major error in the experiment is the size of the CaCO3 chips. As mentioned in the qualitative observation, some marble chips are larger than others, causing that trial to have less surface area while having the same mass. As discussed above, this could potentially cause the reaction to be much slower due to less collision. This can be solved by using a large chips that we can cut by ourselves so that we can control the size, surface area, and volume of the reactants ...read more.

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