Calorimetry, Measuring the Amount of Heat Released or Absorbed During a Chemical Reaction - Research Paper Example

Calorimetry Student’s Name: Student’s Reg. No.: Course Name Course Code: Department: University: Lecturer: Date of submission: Introduction The total amount of heat that is required to increase or raise temperature of any system by one degree Celsius is the specific heat. Normally, heat and temperature are related in such a way that that they expressed in one equation where c is the specific heat capacity. However, if there is phase change in the system the relationships does not exists since there is no temperature change when heat is removed or added in the system. On heating or cooling a substance there would temperature change,, to the object surrounding and internal particles, as indicated by the Specific Heat Capacity, of the substance, the mass, , of the substance and the amount of energy, which is supplied. (Temperature change) …………………………………….(i) A susbstance will remain to have constance temperature when it is undergoing a phase change, which will remain until the phase change is complete. For a phase change to occur the amount of heat energy required it depends on the Latent Heat, L and mass of the substance. (Phase change)……………………………………………… (ii) The amount of energy that is required to breakdown one gram of any substance to liquid state from solid state without change in temperature is the Heat of Fusion. During the breaking of the solid bonds, there is a lot of energy that is left in the substance that is associated with the intermolecular forces that hold the substance in the liquid state. Objectives This experiment aims at determining the specific heat and Latent Heat of Fusion of water with uncertain quantities Experiment A: Specific Heat Materials required Material provided for the experiment include the following: Water, slotted weights, Calorimeter cup; thermometer, thermometer, double-pan balance Power supply; Xplorer GLX measuring probe with Voltage‐Current sensor Experimental procedure Measured the mass of an empty calorimeter and recorded the mass () for calorimeter and the expected error; Poured about 200ML of water into the calorimeter cup; Measured the mass of the calorimeter cup plus water, recorded mass ( and the expected error: Placed the stirrer in the cup; Placed the lid of the calorimeter cup over the cup; Measured the initial temperature of the water using the probe in the base, include the
uncertainty; Continued to measure the temperature of the water, whilst jiggling the stirrer, to ensure that thermometer has reached equilibrium with the water; Set the power supply to 10 V, the resultant current to near to 1 A; Turned on the water heater and recorded the temperature at 1-minute interval for 10 minutes. Recorded the values in the table below; Time (min) Temp (0C) ± ± 0 21.2 1 21.4 2 22 3 22.6 4 23.6 5 24.2 6 24.8 7 25.6 8 26 9 26.4 10 27 Turned off the heater and recorded the temperature until the maximum value was reached; Determined the relationship between the energy that has been used to heat the water and the power of the heater; Results and discussion Mass of calorimeter, Mass of calorimeter with water Temperature, Quantity Value Uncertainty % uncertainty V 10V 0.03 3 I 1A 0.02 2 0.0001 0.01 0.0001 0.01 0.0002 0.16 0.0102 0.080 5203.78 35.7 0.686 But, Figure 1: a plot of ΔT vs t Comparing the theoretical specific heat for water, which is of 4.19x103 Jkg‐1C‐1 it lower than the calculated specific heat, which is, this means water has transferred its heat to the calorimeter thus resulting into higher specific heat value (Clark, 149). Experiment B: Latent Heat of Fusion Materials required Water, crushed ice/ ice cubes, calorimeter cup, thermometer, thermometer, double-pan balance and Xplorer measuring probe. Experimental procedure We measured the mass of the empty calorimeter cup and recorded the measurements as well as the error in the measurement; Poured about 200 mL of water into the calorimeter cup; Measured the mass of the calorimeter cup with the water, Recorded measurements and its 
uncertainty; Placed the stirrer into the cup; Placed the lid of the calorimeter cup over the cup; Using the probe in the base we measured the initial temperature of the water, recorded this temperature including its uncertainty; Measured the initial temperature of the ice in the ice bucket, including the uncertainty; Added approximately 50 g (a decent sized scoop) of ice to the water; Monitored the temperature of the water/ice mixture whilst jiggling the stirrer, and recorded the minimum temperature reached; Once all the ice was melted, measured the final mass of the calorimeter cup with the water; Results and discussion Mass of the empty calorimeter =124.9g Mass of calorimeter with water =332.4g Quantity Value Uncertainty % uncertainty 0.0002 0.096 22.27 0.05 0.22 0 0.01 0 0.003 0.11 0.0001 0.2 4190 - - 2090 - - 869.4 0.834 0.096 11.97 0.15 1.25 208.7 0.417 0.2 10407 140.1 1.346 2149.6 25.15 1.17 4505.56 2.716 Where: initial mass of water initial temperature of water initial temperature of ice Minimum temperature of water Final mass of water Mass of ice Specific heat of water Specific heat of ice Latent heat of fusion of ice From Equation 1, energy used in cooling the water can be determined by: Similarly, using Equation 1 the energy used to heat the ice and then heat the water left after the ice has melted can be determined given by: On the other hand, energy used to melt the ice can be determined using equation 2: In steady state, the amount of energy used in cooling the original water must be equal to the energy used to heat/melt/heat the ice, these expressions can be combined to: …………………………………(iii) Rearranging the above equation (iii), we the Latent heat of fusion of ice, which has a theoretical value of 3.33x105 J kg‐1. Comparing the theoretical value of latent heat of fusion of ice with the calculated latent heat of fusion of ice, theoretical value is higher than the calculated value. However, due the external losses from the walls of the calorimeter, heat of fusion is lost to the environment during the phase change from ice to water, and this result to lower calculated latent of fusion of ice than theoretical value (Avison, 49). Energy lost to the environment From Equation 3 it is assumed that no energy is lost or gained, meaning we assumed that there is no energy transfer between the environment and the system. However, the system it is in reality in contact with the air surrounding thus, there is some energy gained or lost by the system during the experiment. Denoting the lost energy “E-Lost” equation 3 can be written as follows: …………………. (iv) From the above equation, the amount of energy lost between the environment and the system can be calculated while assuming theoretical value of Latent heat of fusion of ice. Conclusion The aim of this experiment to determine the specific heat and Latent Heat of Fusion of water with uncertain quantities as been achieved in that the calculated values for latent heat of fusion and specific heat have been calculated in experiment A and B. In addition, the expected uncertainties were determined as indicated in experiments A and B respectively. However, theoretical values have no large discrepancies from the tabulated values from the graphical analysis. Calculated values vary from theoretical values making calculated specific heat of water higher than theoretical value and the latent heat of fusion of ice having a lower calculated L than theoretical value, which is attributed by the loss between the system and the environment. Works Cited Avison, John, The World of Physics. New Delhi: Nelson Thornes, 2014. Print. Clark, O. E. John The Basics of Heat. The Rosen Publishing Group, 2014. Print. Read More