1. Is the sign of AHxn for an exothermic reaction positive or negative? Why? 2. When 4.21 grams of potassium hydroxide are added to 250. mL of water in a coffee cup calorimeter, the temperature rises by 4.14 °C. Assume that the density and specific heat of the dilute aqueous solution are the same as those of H2O and calculate the molar heat of solution of potassium hydroxide in kJ/mol. C = 4.184 J/g-K al nowy fon Jness Po (5)-Ansg 3. Using Hess' Law, Calculate the standard heat of formation of copper(I) oxide given the following data: A,H° 157.3 kJ/mol CuO(s) Cu(s) + O2(g) 4CuO(s) →2Cu2O(s) + O2(g) A,H° 292.0 kJ/mol tayla ad 060 ses yo Som nobleroyd s solb

1. Is the sign of AHxn for an exothermic reaction positive or negative? Why? 2. When 4.21 grams of potassium hydroxide are added to 250. mL of water in a coffee cup calorimeter, the temperature rises by 4.14 °C. Assume that the density and specific heat of the dilute aqueous solution are the same as those of H2O and calculate the molar heat of solution of potassium hydroxide in kJ/mol. C = 4.184 J/g-K al nowy fon Jness Po (5)-Ansg 3. Using Hess' Law, Calculate the standard heat of formation of copper(I) oxide given the following data: A,H° 157.3 kJ/mol CuO(s) Cu(s) + O2(g) 4CuO(s) →2Cu2O(s) + O2(g) A,H° 292.0 kJ/mol tayla ad 060 ses yo Som nobleroyd s solb

Chemistry by OpenStax (2015-05-04)

1st Edition

ISBN:9781938168390

Author:Klaus Theopold, Richard H Langley, Paul Flowers, William R. Robinson, Mark Blaser

Publisher:Klaus Theopold, Richard H Langley, Paul Flowers, William R. Robinson, Mark Blaser

Chapter5: Thermochemistry

Section: Chapter Questions

Problem 27E: The addition of 3.15 g of Ba(OH)28H2O to a solution of 1.52 g of NH4SCN in loo g of water in a...

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9.83 A student performing a calorimetry experiment combined 100.0 mL of 0.50 M HCl and 100.0 mL of 0.50 M NaOH in a coffee cup calorimeter. Both solutions were initially at 20.0°C, but when the two were mixed, the temperature rose to 23.2°C. (a) Suppose the experiment is repeated in the same calorimeter but this time using 200 mL of 0.50 M HCl and 200.0 mL of 0.50 M NaOH. Will the T observed he greater than, less than, or equal to that in the first experiment, and why? (b) Suppose that the experiment is repeated once again in the same calorimeter, this time using 100 mL of 1.00 M HCl and 100.0 mL of 1.00 M NaOH. Will the T observed he greater than, less than, or equal to that in the first experiment, and why?
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When one mol of KOH is neutralized by sulfuric acid, q=56 kJ. (This is called the heat of neutralization.) At 23.7C, 25.0 mL of 0.475 M H2SO4 is neutralized by 0.613 M KOH in a coffee-cup calorimeter. Assume that the specific heat of all solutions is 4.18J/gC, that the density of all solutions is 1.00 g/mL, and that volumes are additive. (a) How many mL of KOH is required to neutralize H2SO4? (b) What is the final temperature of the solution?
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Given 2Al2O3(s)4Al(s)+3O2(g)H=3351.4kJ (a) What is the heat of formation of aluminum oxide? (b) What is H for the formation of 12.50 g of aluminum oxide?