CHEM102 Lecture Notes - Lecture 25: Heat Capacity, Combination, Calorimetry

ring Calorimetry (く) 80f 11 Part A A calorimeter is an insulated device in which a chemical reaction is contained. By measuring the temperature change, AT, we can calculate the heat released or absorbed during the reaction using the following equation bus A calorimeter contains 280 mL of water at 12.0。C、when 250 g otX (a substance with a molar mass of 76.0 g/mol ) is added, it dissolves via the reaction X(s) +H20(l)-+X(aq) and the temperature of the solution increases to 260 C Calculate the enthalpy change, Δ H. for this reaction per mole of x. Assume that the specific heat of the resulting solution is equal to that of water 14.18 J/( surroundings. Express the change in enthalpy in kilojoules per mole to three significant figures. View Available Hint(s) q = specific heat × mass × ΔT mic ules Or, if the calorimeter has a predetermined heat capacity, C, the equation becomes C)L, that At constant pressure, the enthalpy change for the Settin reaction, AH, is equal to the heat, g,: that is, se Toc but it is usually expressed per mole of reactant and with a sign opposite to that of q for the surroundings. The total internal energy change, AE (sometimes referred to as Δ is the sum of heat, g, and work done, w kJ/mol However, at constant volume (as with a bomb calorimeter) te = 0 and so ΔE=%- Submit signme Part 涨 boo F rs F7

Calorimetry is the measurement of heat transfer. Devices that measure the amount of heat released or absorbed during a process are called calorimeters. A Coffee cup calorimeter is the simplest calorimeter and is often used to measure the heats of chemical reactions at constant pressure (also called enthalpies). This calorimeter consists of a Styrofoam cup with a plastic lid and a thermometer. in today's workshop, we will use calorimetry to calculate the standard molar enthalpy of reaction or the enthalpy change that occurs in a system when 1 mole of matter is transformed by a chemical reaction at 1 atm: _Delta H = q_rxn (in J/mole, at constant P and p V-work only), where q = cm Delta T A student wants to measure the heat of neutralization reaction. To do this she mixed in a coffer cup calorimeter 35.0 mL of 0.70M HCI solution and 65.0 mL of 0.50M NaOH solution both at 22.0 degree C initially. She then continued to measure the temperature of the mixture for 10 minutes. Write a chemical equation, a complete ionic and a net ionic equation for this reaction.

t Heat of Solution Calorimetry is a method used to measure changes in enthalpy, or heat, that occur during chemical processes. Two common calorimeters are constant-pressure calorimeters and constant-volume (or "bomb") calorimeters. Bomb calorimeters are used to measure combustion and other gas-producing reactions, in which the reaction is observed in a strong, sealed vessel. A simple constant-pressure calorimeter can be made from a foam coffee cup and a thermometer, in which energy changes in a reaction are observed via the change in temperature of the solution in the cup. The idea behind calorimeters is that if they are sufficiently insulated from the outside environment, any energy gained or lost in the chemical reaction will be directly observable as a temperature and/or pressure change in the calorimeter. Part A In the following experiment, a coffee-cup calorimeter containing 100 mL of H2O is used. The initial temperature of the calorimeter is 23.0 C If 9.70g of Caci2 is added to the calorimeter, what will be the final temperature of the solution in the calorimeter? The heat of solution AH, soln of CaCl2 is 82.8 kJ/mol. Express your answer with the appropriate units. Co Value Units Submit Hints My Answers Give Up Review Part incorrect; Try Again; 4 attempts remaining Provide back Continue