Question

25g of ammonium chloride NH₄Cl is dissolved in 100 mL of water at 25°C in an insulated constant-pressure calorimeter. The final temperature of the system is 20°C. Calculate the heat of solution of ammonium chloride assuming that the specific heat capacity of the solution is the same as that of water.Cl) is dissolved in 100 mL of water at 25°C in an insulated constant-pressure calorimeter. The final temperature of the system is 20°C. Calculate the heat of solution of ammonium chloride assuming that the specific heat capacity of the solution is the same as that of water.

Answer 1

The heat of solution for the dissolution of ammonium chloride in water, with a temperature decrease from 25°C to 20°C, is calculated to be 2090 J, indicating an endothermic process.

Step-by-step explanation:

To calculate the heat of solution of ammonium chloride, we can use the formula q = mcΔT, where q is the heat absorbed or released, m is the mass of the solution, c is the specific heat capacity, and ΔT is the change in temperature.

Assuming the specific heat capacity of the solution is the same as water (4.18 J/g°C), and given that the mass of water is 100g, we can calculate the heat of the solution for the temperature change from 25°C to 20°C.

Using the data provided:

• Mass of water: 100g (since 1mL of water roughly equals 1g)
• Specific heat capacity of water: 4.18 J/g°C
• Temperature change (ΔT): 20°C - 25°C = -5°C

Substituting these values into the equation we get:

q = (100g) * (4.18 J/g°C) * (-5°C)

q = -2090 J/p>

Since the temperature decreased, the process is endothermic and the heat of solution is positive: 2090 J. To find the molar heat of solution, divide this by the number of moles of NH₄Cl (25g / molar mass of NH₄Cl).