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Enthalpy of Formation

Q. The ∆Hsol is -15 kJ/ mol and the ∆Hhydration is 700 kJ/mol for dissolving NaI in water, what is the ∆Hlattice for NaI?

Solved • May 4, 2020

Enthalpy of Formation

Q. Potassium perchlorate (KClO4) has a lattice energy of −599 kJ mol−1 and a heat of hydration of −548 kJ mol−1. Find the heat of solution for potassium perchlorate and determine the temperature change that occurs when 10.0 g of potassium perchlorate is dissolved with enough water to make 100.0 mL of solution. (Assume a heat capacity of 4.05 J g−1 °C−1 for the solution and a density of 1.05 g mL−1.)

Solved • May 4, 2020

Enthalpy of Formation

Q. When CH4 was reacted with excess Cl2 according to the chemical equation shown below, the enthalpy of the reaction was calculated to be -708 kJ per mol CH4. What is the value of ΔHrxn for the reaction as written?

Solved • May 1, 2020

Enthalpy of Formation

Q. Consider the following reaction: 2 Mg(s) + O2 → 2 MgO(s) a. Is the reaction exothermic or endothermic? b. calculate the amount of heat transferred when 3 g of Mg(s) reacts at constant pressure. c. How many grams of MgO are produced during an enthalpy change of 100.0 kJ? d. How many kilo joules of heat are absorbed when 8 g of MgO(s) are decomposed into Mg(s) and O2(g) at constant pressure? AH = -1204 kJ.

Solved • Apr 23, 2020

Enthalpy of Formation

Q. At a festival, spherical balloons with a radius of 290 cm are to be inflated with hot air and released. The air at the festival will have a temperature of 25°C and must be heated to 100°C to make the balloons float. 2.00 kg of butane (C4H10) fuel are available to be burned to heat the air. Calculate the maximum number of balloons that can be inflated with hot air.

Solved • Apr 29, 2020

Enthalpy of Formation

Q. At a festival, spherical balloons with a radius of 90.0 cm are to be inflated with hot air and released. The air at the festival will have a temperature of 25°C and must be heated to 100°C to make the balloons float. 3.00 kg of propane (C3H8) fuel are available to be burned to heat the air. Calculate the maximum number of balloons that can be inflated with hot air.

Solved • Apr 27, 2020

Enthalpy of Formation

Q. Consider the following substances: HCl(g) F2(g) HCl(aq) Na(s) Which response includes AL of the substances listed that have ΔHf° = 0? 1. HCl(g), Na(s) and F2(g) 2. HCl(g) and Na(s) 3. HCl(g), Na(s), HCl(aq) and F29g) 4. na(s) and F2(g) 5. Na(s)

Solved • Apr 22, 2020