Question

A reaction known to release 2.00 kJ of heat takes place in a calorimeter containing 0.200 L of solution and the temperature rose by 4.46◦C. When 100 mL of nitric acid and 100 mL of sodium hydroxide were mixed in the same calorimeter, the temperature rose by 2.01◦C. What is the heat output for the neutralization reaction?

Answer 1

Answer:

There is 900.48 J heat released. (q = -900.48, the reaction is exothermic)

Explanation:

Step 1: Data given

Heat released = 2.00 kJ  (Since it's heat released q = -2.00 kJ)

volume of the solution = 0.200 L

Temperature rise = 4.46 °C

Volume nitric acid = 100 mL

Volume sodium hydroxide = 100 mL

Temperature rise in this case = 2.01 °C

Step 2: Calculate heat capacity of the calorimeter

Heat capacity C = q / ΔT = 2.00 kJ / 4.46 °C = 0.448 kJ/ °C = 448 J/°C

Step 3: The neutralization reaction

q(neutralization) = - q(calorimeter) = -C(calorimeter) *ΔT = -448 J/°C * 2.01 °C

q(neutralization) = -900.48 J

Since q <0  the reaction is exothermic

If q is negative, then energy has been released from the system to its surroundings,