Question

A 107.2 mL sample of 1.00 M NaOH is mixed with 53.6 mL of 1.00 M H₂SO₄ in a large Styrofoam coffee cup; the cup is fitted with a lid through which passes a calibrated thermometer. The temperature of each solution before mixing is 22.45 °C. After adding the NaOH solution to the coffee cup and stirring the mixed solutions with the thermometer, the maximum temperature measured is 32.10 °C. Assume that the density of the mixed solutions is 1.00 g/mL, that the specific heat of the mixed solutions is 4.18 J/(g·°C), and that no heat is lost to the surroundings.

Part A:

Calculate the enthalpy change per mole of H₂SO₄ in the reaction. (units need to be in kJ/mol)

Answer 1

Step (1)

Total volume of solution = volume of NaOH + Volume of H₂SO₄

_{total volume of solution = 107.2mL + 53.6mL}

_{total volume of solution = 160.8ml}

_{step (2)}

Mass of solution = (volume of solution)(density of solution)

Mass of solution = (160.8mL)(1g/mL)

Mass of solution = M= 160.8g

Step (3)

∆H = mc∆T

Where ∆H = Change in entalpen

M = mass of solution

C = specific heat = 4.18J/g°C

∆T = temperature change = (32.10 - 22.45)°C= 9.65°C

∆H = (160.8g)(4.18j/g°C)(9.65°C)

∆H = 6486.1896j = 6.486×10³ J

∆H = 6.486kJ

Step (4)