dolocator assignment t-take Use the References to access important values if nee
ID: 1032614 • Letter: D
Question
dolocator assignment t-take Use the References to access important values if needed for thiz question. When a solid dissolves in water, heat may be evolved or absorbed. The heat of dissolution (dissolving) can be determined using a coffee cup calorimeter In the laboratory a general chemistry student finds that when 1.53 g of CaCl:(s) are dissolved in I112.00 g of water, the temperature of the solution increases from 23.54 to 25.98 °C Cardboard or Styrofoam lid The heat capacity of the calorimeter (sometimes referred to as the calorimeter constant) was determined in a separate experiment to be 1.59 Nested Stynofoam cups Based on the student's observation, calculate the enthalpy of dissolution of CaCl:(s) in kJ mol Reaction occurs in solution, Assume the specific heat of the solution is equal to the specific heat of water kI mol Submit Answer Retry Entire Group t more grop attempts remaining UpExplanation / Answer
mass of solution = 112 + 1.53 = 113.53 g
specific heat = 4.18 J/ g oC
temperature difference = 25.98 - 23.54 = 2.44 oC
Q = m Cp dT + Cp dT
= 113.53 x 4.18 x 2.44 + 1.59 x 2.44
= 1162.9 J
moles of CaCl2 = 1.53 / 111 = 0.01378 mol
enthalpy = - Q / n = - 1.1629 / 0.01378
enthalpy = - 84.4 kJ/mol
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