Question

2.00 L of 0.500 M H2SO4 (density = 1.030 g/mL) at 25.000°C is mixed with 200. g of a NaOH solution, also at 25.000°C. After stirring, the temperature of the solution is 36.820°C. Calculate q for the reaction. (Assume the specific heat capacity of each solution is 4.184 J/g°C. ) Is the reaction exothermic or endothermic?

Answer 1

Answer:

Q = 111.8 kJ;

The reaction is endothermic.

Explanation:

The heat of the mixture can be calculated by the equation:

Q = m*c*ΔT

Where Q is the heat, m is the mass of the solution, c is the specific heat, and ΔT is the variation in the temperature (fina - initial).

The mass of H₂SO₄ is the volume multiplied by its density:

mH₂SO₄ = 2000 mL * 1.030 g/mL = 2060 g

Then the total mass is:

m = 2060 + 200

m = 2260 g

Q = 2260*4.184*(36.820 - 25.000)

Q = 111,468.03 J

Q = 111.8 kJ

The reaction is endothermic because the solution is absorbing heat (Q > 0), which can be noticed by the increase in the temperature. When the reaction loses heat, it is exothermic and the temperature decreases.