A calorimeter contains 35.0 mLmL of water at
15.0 ∘C∘C . When 2.50 gg of XX (a
substance with a molar mass of 81.0 g/molg/mol ) is
added, it dissolves via the reaction
X(s)+H2O(l)→X(aq)X(s)+H2O(l)→X(aq)
and the temperature of the solution increases to
26.0 ∘C∘C .
Calculate the enthalpy change, ΔHΔHDelta H, for this
reaction per mole of XX.
Assume that the specific heat of the resulting solution is equal
to that of water [4.18 J/(g⋅∘C)J/(g⋅∘C)], that density
of water is 1.00 g/mLg/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.
Part B:
Consider the reaction
C12H22O11(s)+12O2(g)→12CO2(g)+11H2O(l)C12H22O11(s)+12O2(g)→12CO2(g)+11H2O(l)
in which 10.0 gg of sucrose, C12H22O11C12H22O11,
was burned in a bomb calorimeter with a heat capacity of
7.50 kJ/∘CkJ/∘C. The temperature increase inside the
calorimeter was found to be 22.0 ∘C∘C. Calculate the change in
internal energy, ΔEΔEDelta E, for this reaction per mole of
sucrose.
Express the change in internal energy in kilojoules per mole to
three significant figures.
- Part A A Calorimeter Contains 35 0 Mlml Of Water At 15 0 C C When 2 50 Gg Of Xx A Substance With A Molar Mass Of 81 1 (82.36 KiB) Viewed 31 times
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 × AT Or, if the calorimeter has a predetermined heat capacity, C, the equation becomes q=Cx AT At constant pressure, the enthalpy change for the reaction, AH, is equal to the heat, q; that is, AH =qp 9² but it is usually expressed per mole of reactant and with a sign opposite to that of g 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 However, at constant volume (as with a bomb calorimeter) w = 0 and so AE = Review | Constants Periodic Table Check the sign of your answer. A positive sign indicates that heat is absorbed. Your answer has units of joules per mole. The enthalpy should be expressed in kilojoules per mole of reactant. You may want to review Hint 1. How to approach the problem. Part B Consider the reaction C12H22O11 (8) + 120₂ (g) 12CO₂(g) +11H₂O(1) in which 10.0 g of sucrose, C12II22011, 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) IVE| ΑΣΦ 4 Ĉ ? AE= kJ/mol Submit Provide Feedback Next >