orimetry Lab 2- c Trees-2 Practical Re 1-2 copy Constants I Periodic Table A cal
ID: 579975 • Letter: O
Question
orimetry Lab 2- c Trees-2 Practical Re 1-2 copy Constants I Periodic Table 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: Fuarh b. Practical 1 Re 3 s-3 V4 q = specific heat × mass × T Or, if the calorimeter has a predetermined heat capacity, C, the equation becomes BIO 123L PRACTICAL At constant pressure, the enthalpy change for the reaction, AH, is equal to the heat, qpi that is, but it is usually expressed per mole of reactant and with a sign opposite to that of q for the surround ings. The total internal energy change, E (sometimes referred to as U), is the sum heat q, and work done, w: e ice Tab bbcwHowever, at constant volume (as with a bomb calorimeter) to 0 and so E-%- Part 6 n:Explanation / Answer
A.
Mass of water = volume * density = 25.0 mL * 1.00 g. / mL = 25.0 g.
Specific heat of solution = 4.18 J/g.0C
Change in temperature = 26.5 - 12.5 = 14.0 0C
Heat change = mass * specific heat * change in temperature = 25.0 * 4.18 * 14.0 = 1463. J
Number of moles of X = mass / molar mass = 2.50 / 42.0 = 0.0595 mol
Therefore, Change in enthalpy, deltaH = q / n = 1463 / 0.0595 = 24578 J = 24.6 kJ/mol
B.
Heat change = calorimeter capacity * change in temperature = 7.50 * 22.0 = 165. kJ
Number of moles of sucrose = mass / molar mass = 10.0 / 342 = 0.0292 mol
Therefore, change in internal energy, deltaE = q / n = 165. / 0.0292 = 5643. kJ/mol
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