Unit 18B. The Rate of Reaction Between HCl and CaCO3

Unit 18B Experiment 1: The rate of reaction between HCl and CaCO3 Aim: To investigate the effect of changing the concentration on the rate of a reaction between HCl and CaCO3. Introduction: In this experiment, the rate of reaction will be studied between HCl and CaCO3. By investigating this reaction, the factors that affect reaction rates will be understood. Factors such as concentration, temperature and surface area will be explored in order to find out how these affect the rate of reaction. Risk Assessment: HCl- Can cause severe burns. Inhalation can irritate the respiratory system. Avoid contact with eyes and skin. Wear safety goggles and gloves to protect yourself. CaCO3- Irritation of the respiratory system. Avoid breathing in dust particles by working in a ventilated area. Burns may happen if the temperature is too hot. Wear gloves and safety goggles. Equipment List: Gas syringe Conical flask CaCO3 Dilute HCl Stand, boss and clamp Measuring cylinder Stop clock Method/procedure: Variables Independent- the temperature Dependent- the time it takes for the CaCO3 to react with HCl and water. Control- same volume of the amount of hydrochloric acid Results: Start temperature HCl (cm3) CaCO3 (cm3) Water(cm3) Time taken for the cross to (°C) 23 22 25 22 20 5 5 5 5 5 50 40 30 20 10 disappear (s) 15.94 20.44 14.12 12.28 24.50 0 10 20 30 40 Graph of CaCO3 Concentration of CacO3 (cm3) Concentration of CaCO3 Over time 60 50 40 30 20 10 0 15.94 20.44 14.12 12.28 24.5 Time taken for cross to disappear (s) Calculations: 40-30= 10 10-20=-10 Gradient= -1 Conclusion- The concentration as it goes down the slope decreases as the time taken for the cross to disappear increases. The slope is down so the gradient will be negative. Reactants and products Mr Mr of CaCO3= 44.01g/mol Mr of water= 18.02g/mol Mr of HCl=36.46g/mol Compare results to online results The graph here shows the curve going up which means the gradient would be positive. The slope of the concentration increases as the time increases as well. Compared to my graph this is more accurate because my graph shows the slope decreasing which would make the gradient negative. My graph shows a straight line instead of a curved which has something to do with the value of the time because the points were placed incorrectly. Talk about percentage error Percentage error of the measuring cylinder= 0.3% % error of gas syringe= 0.005% % error of conical flask= 0.08% The percentage error of these is estimated close to the true value. Experiment 2: The rate of reaction between HCl Aim- Investigate the effect of change in temperature in rate of reaction Risk assessment: Na2CO3- eye irritation wear goggles to protect eyes. Skin irritation was hands and wear gloves to protect yourself. HCl- it is corrosive so it may cause eye damage if it goes in the eyes. Causes severe burns to the skin. Wear goggles, gloves and lab coats to prevent it from going near your skin. Spillages- clean it up as you can slip and trip. Method: Equipment: Measuring cylinder Trough Water Dilute HCl Na2CO3 Conical flask Measuring cylinder Bung Variable Control- Sodium carbonate solution Independent- Time taken Dependent- Temperature Results: HCl (ml) Na2CO3 Temperature (°C) 50 50 50 50 50 5 5 5 5 5 20 (room temperature) 30 40 50 60 Time taken for the cross to disappear (s) 22 17 13 11 7 Effect of temperature on the time it takes to disappear 70 Temperature (°C) 60 50 40 30 20 10 0 7 11 13 17 Time taken for cross to disappear (s) Calculations Gradient= -2 1/2 50-30=20 9-17= -8 so 20/-8 is -2.5. 22 Conclusion: The temperature as it goes down the slope decreases as the time taken for the cross to disappear increases. The slope is down so the gradient will be negative. The slope decreases in a straight line and then decreases further. Mr of Na2CO3= 106g/mol Mr of HCl= 36.46g/mol Mr of CO2= 44.01g/mol Mr of water= 18.02g/mol Mr of NaCl= 55.84g/mol Comparison: This graph shows the reaction between sodium thiosulphate and HCl. The graph I did is kind of similar except it doesn’t have a curve and the graph is about the reaction between HCl and Na2CO3. The graph here shows a curve and shows the temperature decrease as the time increases similar to mine. % error of equipment Conical flask- 0.08% Measuring cylinder- 0.3% P5: