Description Physical Science (PHSC 100) Virtual Lab Expt. # 5: Heat Loss and Change in Temperature ...

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Description Physical Science (PHSC 100) Virtual Lab Expt. # 5: Heat Loss and Change in Temperature Name: ________________________ Section: _______ Date: ______ Note on this virtual experiment Read the introductory principle, procedure and experimental materials outlined below, and understand as to how this virtual experiment would be conducted under real lab condition to generate the data supplied in Tables 1 below. After clearly understanding the procedure and the formula for the calculations, complete the blank columns with calculated data, write brief discussions as per the guideline, and Submit it back in the Drop Box. Introduction Heat always flows from objects of high temperature to those of low temperature, until the temperature reaches equilibrium. If hot water is left at room temperature it will lose heat until the temperature reaches its surroundings. The amount of heat lost (Q) is proportional to the mass and specific heat capacity of the material and the change in temperature. This can be determined using the following equation: Q = mc?T Where Q is the quantity of heat lost in calories, m is the mass (in gram, 1 ml = 1g for water), c is the specific heat capacity (1.0 cal/g 0C for water) and ?T is the change in temperature in Celsius. The objective of this experiment is to study the quantity of heat lost and the change in temperature of hot water under covered and uncovered conditions. Materials Required • Hot plate • cardboard covers with holes • Beaker • Styrofoam cups • Thermometer • Graduated cylinder • Stopwatch Procedure Heat Loss and Change in Temperature A litter of water is brought to boiling in a pan on an electric hotplate. 100 ml of hot water is poured into cup #1 and another 100ml of hot water into cup #2 and the temperatures measured with separate thermometers. Cup # 1 is left uncovered and cover cup #2 is covered with a piece of cardboard with a hole in the center for inserting a thermometer. The thermometers are left to stay in both covered and uncovered cups for continuous temperature measurement. The initial temperature for both covered and uncovered cups is measured and recorded in the appropriate column on the data table for both covered and uncovered at 0 minute and from then on at 10-minnutes intervals for 40 minutes. Data Calculation and Interpretation Assignment First calculate the change in temperature (?T) for each time interval always by subtracting the temperature at each time interval from the initial temperature (temperature at 0 min) and enter values in the change in temperature column. Do this for both covered and uncovered cups. Then calculate the total quantity of heat (Q=mcT) and heat loss (Q = mc?T) in calories for each time interval for both covered and uncovered cups and enter values in the appropriate column. Where Q = total quantity of heat, m = mass of water (1 ml=1g), c= specific heat of water, which is 1cal./g/0C, and ?T =change in temperature in 0C. Calculate and fill out all blank columns.Table. 1. Heat Loss / Heat Gain Q = M.C.?T Q = quantity of heat, M = mass of water (1 ml of water = 1g) C = specific heat capacity of water (1cal/g/0C), ? T = change in temperature Time (min) Uncovered Cup Covered cup Heat Ratio: Total Q-uncovered Total Q-covered Temp (T) cup #1 (0C) Total Q(MCT) (Cal.) ? T (0C) From initial Heat loss Q= MC?T (cal.) cumulative Temp.(T) cup #2 (0C) Total Q (MCT) (Cal.) ? T (0C) From initial Heat loss Q= MC?T (cal.) (cumulative) 0 min 85 -- --- 85 -- --- 10 min 52 66 20 min 45 55 30 min 39 47 40 min 34 41 Discussion In the lined space below, briefly describe your experimental results by comparing the change in temperature (T) and total quantity of heat (Q) through time, for the covered and uncovered cups. Also give possible explanations for the differences in the rate and quantity of change in Q and T values under the two conditions (covered and uncovered). What does the heat (Q) ratio, between the uncovered and covered cups, through time indicate to you? ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________