During the experiment, the group were able to perform the following objectives; to compute the heat capacity of a Styrofoam-cup calorimeter, and also to compute the heat of neutralization of 1.0 M hydrochloric acid and 1.0 M sodium hydroxide, the heat of dilution of concentrated sulfuric acid, and the heat of solution of solid ammonium chloride The sixth experiment was named "Calorimetry" wherein it is the measurement of how much heat is gained or released by a system as a chemical reaction occurs within it. The experiment has subtopics namely; Preparation of the Two Styrofoam-Cup Calorimeters, Determination of the heat capacity of calorimeter 1, Heat of neutralization of 1.0 M Hydrochloric Acid and 1.0 M sodium Hydroxide, and lastly Heat of Dilution of Concentrated Sulfuric Acid. The experiment was done in the allotted time and it was quite difficult for us because of the wide range of equation.
Calorimetry, exothermic, endothermic, and heat capacity
Calorimetry is the measurement of how much heat is gained or released by a system as a chemical reaction occurs within it. The heat lost or gained in a chemical reaction is the heat of reaction. The laboratory device in which quantities of heat can be measured is called calorimeter. There are two types of calorimeter: The bomb calorimeter and the open calorimeter. In a bomb calorimeter, the volume of the system is constant. The heat measured equals the change in the internal energy of the system. In an open calorimeter, the pressure of the system is constant.
Heat measurements are made by mixing known amounts of reactants in a calorimeter and letting them react. In an exothermic reaction, the chemical reaction gives off heat to the surroundings. The heat is absorbed by the calorimeter and its temperature rises. In an endothermic reaction, the chemical reaction absorbs heat from the surroundings. The heat is absorbed from the calorimeter and its temperature falls.
The SI unit of energy is the joule (J) and one calorie (cal) is equal to 4.184J. The joule and the calorie are relatively small units for measurements of thermochemical values. The heat capacity (C) of a given mass of a substance is the amount of heat required to raise the temperature of the mass by one degree Celsius. Specific heat (s) is the amount of heat required to raise the temperature of one gram of the substance by one degree Celsius. Experimental Section:
LIST OF CHEMICALS
1M hydrochloric acid, ammonium chloride, 1M sodium hydroxide
, phenolphthalein, Concentrated sulfuric acid, distilled water. LIST OF APPARATUS
2 thermometers, 2 Styrofoam-cup calorimeters, 10-mL graduated cylinder, 50-mL graduated cylinder, iron stand, iron ring, Bunsen burner, wire gauze, electronic balance, 150-mL beaker PROCEDURE
Preparation of the Two Styrofoam-Cup Calorimeters. A Styrofoam-cup calorimeter consists of two Styrofoam cups nested together with a cover. A hole is made in the cover for the insertion of the thermometer. Make sure that the two thermometers will not interchange. Determination of the Heat Capacity of Calorimeter 1. Place 50 mL of cold water (distilled water at room temperature) in calorimeter 1. Put the cover and determine its temperature (Tcold ) by immersing the thermometer for one minute. Place 50 mL of hot water with temperature between 55°C and 60°C in calorimeter 2. Put the cover and determine its temperature ( Thot ) after one minute. Immediately pour the hot water in calorimeter 2 to the cold water in calorimeter 1. Cover and determine the highest temperature ( Tfinal ) reached. Make 2 trials. Calculate the heat lost by the hot water in joules. The specific heat of water is 4.184 J/g-°C. The density of water is 1 g/mL. The mass of water is the product of its volume and density ( qhot = mhots(Tfinal – Thot) ). Compute the heat gained by the cold water in joules. (qcold = mcolds(Tfinal – Tcold)). Determine the heat gained by...
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