- Level: International Baccalaureate
- Subject: Chemistry
- Word count: 789
Design -How does the surface area of Calcium carbonate (CaCO3) affect the rate of reaction with dilute hydrochloric acid (HCl)?
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Introduction
Horizon International School School code: 006048 Session: May 2013 Candidate name: Zwe Kyaw Zwa Candidate number: 006048-004 Session number: 60101 Subject level: Higher Level Assessment D DCP CE DESIGN Research Question How does the surface area of Calcium carbonate (CaCO3) affect the rate of reaction with dilute hydrochloric acid (HCl)? Variables Independent Variable: Size of Calcium carbonate Dependent Variable: Volume of Carbon dioxide produced Controlled Variables: Temperature Pressure Concentration of dilute hydrochloric acid Mass of Calcium carbonate Time interval Background and Theory To determine the effect of surface area on the rate of reaction, a known mass of calcium carbonate granules and powder are each placed in a flask, into which standard dilute hydrochloric acid is added. An acid reacts with a carbonate to give a chloride, water and carbon dioxide. ...read more.
Middle
also indicates the speed of the reaction; the less reaction time needed, the faster is the reaction. Since the concentration of HCl(aq) and mass of CaCO3 are constant, the volume of CO2 produced is constant. However, the more finely divided a solid is, the larger is its surface area. According to the collision theory, the rate of a reaction is directly proportional to the number of effective collisions per second between the reactant molecules. Increasing the surface area increases the number of effective collisions per unit time. Therefore, powdered calcium carbonate reacts much faster with dilute hydrochloric acid than if the same mass is present as granules of marble or limestone. Apparatus * Mortar and pestle * Flask and bung * Thistle funnel * Graduated gas syringe * Stopwatch Chemicals * 1 M 0.025 dm3 dilute hydrochloric acid (HCl) ...read more.
Conclusion
6. The same mass (10 g) of calcium carbonate granules were obtained and grounded to fine powder in a mortar using a pestle. 7. The powder was transferred to the flask and the above procedures were repeated, measuring the volume of carbon dioxide produced every 15 seconds interval. 8. Another graph of volume of carbon dioxide produced against time was plotted on the same axes. Table of Results Table 1: Calcium carbonate granules Volume of CO2 (cm3) Time (seconds) Table 2: Calcium carbonate fine powder Volume of CO2 (cm3) Time (seconds) Graph Conclusion The gradient of the curve for calcium carbonate fine powder is steeper than that for calcium carbonate granules. Therefore, the rate of reaction for the fine powder is faster than that for the granules. When the reactants are reacted completely, the rate becomes constant in both reactions. ...read more.
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