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

To calculate the heat for the reaction, we use the specific heat capacity formula and conclude that the reaction is exothermic because the temperature increases indicating that heat is being released.

Step-by-step explanation:

To calculate the heat q for the reaction between sulfuric acid and sodium hydroxide, we can use the specific heat capacity formula: q = m × c × ΔT, where m is the mass of the solution, c is the specific heat capacity, and ΔT is the change in temperature.

First, we need to calculate the total mass of the final solution. We have 2.00 L of H₂SO₄, which has a density of 1.030 g/mL, hence the mass of the H₂SO₄ solution is 2060 g (2.00 L × 1000 mL/L × 1.030 g/mL). Then, adding 200 g of NaOH solution gives a total mass of 2260 g for the final mixture.

Using the formula:

• q = 2260 g × 4.184 J/g°C × (36.820°C - 25.000°C)

The reaction is exothermic because the temperature increases, indicating that heat is being released.

Answer 2

Q = 111.8 kJ;

The reaction is endothermic.

Step-by-step 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.