Question

When 40.0 mL of 1.00 M H2SO4 is added to 80.0 mL of 1.00 M NaOH at 20.00°C in a coffee cup calorimeter, the temperature of the aqueous solution increases to 29.20°C. If the mass of the solution is 120.0 g and the specific heat of the calorimeter and solution is 4.184 J/g • °C, how much heat is given off in the reaction? (Ignore the mass of the calorimeter in the calculation.)
Use q equals m C subscript p Delta T..
4.62 kJ
10.0 kJ
14.7 kJ
38.5 kJ

Answer 1

ΔT = 29.20 − 20.00 = 9.20 °C
q = m c ΔT = (120.0 g)(4.184 J/g·°C)(9.20 °C) = 4.62 × 10^3 J = 4.62 kJ

The solution (calorimeter) absorbs 4.62 kJ, so the reaction gives off 4.62 kJ (q_rxn = −4.62 kJ). Answer: 4.62 kJ.