In a calorimetry experiment, 2.14 g of NH4Cl is dissolved in 100.0 mL of water. The temperature drops by 1.43°C. Calculate the molar heat of solution for NH4Cl.
To calculate the molar heat of solution for NH4Cl, we need to use the equation:
q = m * c * ΔT
Where:
- q is the heat absorbed or released
- m is the mass of the substance in grams
- c is the specific heat capacity of water (approximately 4.18 J/g°C)
- ΔT is the change in temperature in degrees Celsius
First, we need to calculate the heat absorbed or released (q). Since the temperature dropped, we can determine that heat was released. Therefore, q is negative.
q = -m * c * ΔT
Now, let's calculate the heat:
q = -2.14 g * 4.18 J/g°C * (-1.43°C)
q = 13.584 J
Next, we need to calculate the moles of NH4Cl dissolved using its molar mass.
Molar mass of NH4Cl = 14.01 g/mol (atomic mass of nitrogen) + 4 * 1.01 g/mol (atomic mass of hydrogen) + 35.45 g/mol (atomic mass of chlorine)
Molar mass of NH4Cl = 53.49 g/mol
moles of NH4Cl = mass of NH4Cl / molar mass of NH4Cl
moles of NH4Cl = 2.14 g / 53.49 g/mol
moles of NH4Cl = 0.040 moles
Finally, we can calculate the molar heat of solution by dividing the heat released (q) by the moles of NH4Cl dissolved.
Molar heat of solution = q / moles of NH4Cl
Molar heat of solution = 13.584 J / 0.040 moles
Molar heat of solution = 339.6 J/mol
Therefore, the molar heat of solution for NH4Cl is 339.6 J/mol.