Question

Bonus Chapter 6 Question Page 176.12412 A student had five coffee cup calorimeters, each containing 60.0. mL of 0.833 M NaOH(aq) and all at room temperature (25.0°C) and pressure (1.00 atm). The student planned to add a weighed quantity of solid diprotic L-ascorbic acid, C.HO, to each beaker, stir, and measure the increase in temperature. The student ran out of time and was unable to complete the experiment. Her data is as follows: Experiment Mass of Ascorbic Acid, g 2.20 4.40 2 Final Temperature, "C 26.7 28.3 31.7 31.6 13.22 17.62 1. (2pts) Is this an exothermic or an endothermic reaction? Justify your answer. 2. (2pts) Write a balanced chemical equation for this reaction. Remember that ascorbic acid is diprotic, meaning that it has two acidic hydrogen atoms. 3. (2pts) For each experiment, indicate the limiting reagent. Justify your choice. You can answer this without any calculations. 4. (2pts) Predict the final temperature that the student would have observed in experiment 5. Justify your answer. 5. (4pts) Estimate AH' for the balanced chemical equation under the temperature and pressure conditions in the student's lab by using the student's data. Assume that the densities of all solutions are 1.00 g/mL. 6. (2pts) Given the following data, calculate the AH', of salt produced by this reaction AH'rH2O(l) - 285.8 kJ/mol AH'NaOH(S) - 425.8 kJ/mol AH'NaOH(aq) - 470.1 kJ/mol AHC6H306 () AH'C6H5O6 (aq) - 1137.2 kJ/mol

Answer 1

a Cid: Absorbic O-H C6H₂O6 176-12 gmot grenout / generate AS temperature is increased on heat is and increased the temperature OL System .. - Exothermic reaction 2 C6 Hp Of (6) + NaOH - CC H₂O Ną +2H20co? NaOH 6o.omL of 6.893 M = 0.833 x 2 60 = 0.04998 moles= 49.98 monte 1000 + moms tinitineragam 18.99x2 Absorbicaced o olmal Amount Amdent/MoN & no Domoly (Ammoles limiting reag Abs Naott no olemeler 22.98Absorbcoud 282950 249.961 Both are ncarly 3 8.81 99.92 L N GOH 4 T 13-22 150 5117-62 200 2005 50 T100050 15000 Naolt NaOH FONIMALIS HP- co FAN MINI TUTAN RITTATA ROTINET Attie F

7.2 2:12: IM'' 4. has increased Results 316. since overall energy released in Similar to Previous Condition as Naotco limit reagent but Amour of substance has increased ax is small increak overall temperature. where density of all lections = 1.00 g/mL s totd 60mL) bogor solvent we coll Consider coater! 4-184 J/gk. Gog) 251.04 I Increase in temperatux = 6 - 257044b = 1.506 247/49.95 mmily DH. = 30.125 kJ/mole Leibsonicard (5) Hro Nao(3) + 2x [-285) 32X(-970-1) + 1160-3 47 Imate +x=-30 4 Il mole 2--156041/mole Do te of Cc H & Q na -1580 UI/mole QIP OUT INFO