Temperature (EC) 22 22 22 4 Table 1: Temperature vs. Time Time (min) 1 Imin 2 amin 3 3 min Amin 5 (Add hot water here!) min 6 oma 7 Amin 7:30 8:00 Smin 8:30 9:00 amin 9:30 10:00 Tomin 10:30 600 400 390 389 38 380 38 370 379 Calculations: (a) Make a plot of temperature vs. time in minutes. You should obtain a sigmoid or reverse sigmoid curve depending upon whether the reaction is exothermic or endothermic. (b) Your instructor will help you to determine AT. This will be the change in temperature for the cold water and the calorimeter. (c) Heat lost by hot water is qu=B TH Cam (TBT) Where T-maximum temperature (reached after mixing) and T - initial temperature of the hot water just before it is poured into the calorimeter (see 4.4 V above) $ From the volume of the hot water, calculate the mass assuming the density of water to be 1.00 g/mL. $ Calculate the number of moles of hot water li using this mass calculated and the molecular wt of water. $ Cum of water is obtained from your text book. (d) heat gained by cold water is qen Cam (AT) Where AT is as discussed with your instructor and is molar heat capacity of water. (e) heat gained by calorimeter and accessory, the thermometer, is qca = Ca (AT). (1) 4h - 4+ cal YB n Cpum (TBT)=ne Cpm AT + Ccal AT YB ni Cpm (TBT) -(nc Cp.m + Cal) AT B n Com.(T/BT) B ne Cpm = Cal AT *You cannot have a negative heat capacity. If you do, check and recheck your calculation or ask for your instructor=s help! *Your Cal value should be 5.997j/deg for the calorimeter provided. (8) Calculate the % error. B. Heat of dissolution of NH.CH (i) Measure and pour 50.0mL of distilled water in the dry calorimeter. (ii) Wait five minutes. During this wait period weigh 5.000 g of NH Clo, and keep in a safe place. (iii) After the five minutes wait, start temperature B time measurements at one minute interval for five minutes. (iv) Quickly open the calorimeter at the fifth minute and pour all the 5.000g of NH.CI() into the water. (v) Close and stir vigorously and continue temperature B time measurements every 30 seconds for another three minutes. (vi) Make a temperature vs. time plot as in part A of this procedure