Answer Happy

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: q= specific heat x mass x AT Or, if the calorimeter has a predetermined heat capacity, C, the equation becomes q=C x AT At constant pressure, the enthalpy change for the reaction, AH, is equal to the heat, qp; that is, ΔΗ = qp 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 AU), is the sum of heat, q, and work done, w: AE=q+w = 0 However, at constant volume (as with a bomb calorimeter) w = and so AE = qv.
Part A A calorimeter contains 22.0 mL of water at 12.5 °C. When 1.40 g of X (a substance with a molar mass of 61.0 g/mol) is added, it dissolves via the reaction and the temperature of the solution increases to 25.0 °C. Calculate the enthalpy change, AH, for this reaction per mole of X. Assume that the specific heat of the resulting solution is equal to that of water [4.18 J/(g. °C)], that density of water is 1.00 g/mL, and that no heat is lost to the calorimeter itself, nor to the surroundings. Express the change in enthalpy in kilojoules per mole to three significant figures. ► View Available Hint(s) AH = Π| ΑΣΦ www. X(s)+H2O(1)→X(aq) ? kJ/mol
Part B Consider the reaction C12 H22 O11 (s) + 1202 (g)→12CO2(g) + 11H₂O(1) in which 10.0 g of sucrose, C12 H22 O11, was burned in a bomb calorimeter with a heat capacity of 7.50 kJ/°C. The temperature increase inside the calorimeter was found to be 22.0 °C. Calculate the change in internal energy, AE, for this reaction per mole of sucrose. Express the change in internal energy in kilojoules per mole to three significant figures. ► View Available Hint(s) ΔΕ = 5 ΑΣΦ ? kJ/mol