Question

Following the procedure in the lab manual, a student added 0.782 g of metal oxide to 99.5 ml of 3 M HCl in a calorimeter at an initial temperature of 20.3 °C and acquired temperature as a function of time data. A plot of these data was constructed, an extrapolation to time zero was made, and the final temperature was determined to be 22.1 °C. What is the heat of reaction (ΔH) in units of kJ/mol of metal oxide? Assume the heat capacity of the calorimeter is 85 J/°C.

Answer 1

To calculate the heat of reaction (ΔH) in units of kJ/mol of metal oxide, we can use the equation q = mCΔT. By substituting the given values into the equation and solving for ΔH, we can determine the answer.

Step-by-step explanation:

To determine the heat of reaction (ΔH) in units of kJ/mol of metal oxide, we can use the equation q = mCΔT, where q is the heat gained or lost, m is the mass of the solution, C is the heat capacity of the solution, and ΔT is the change in temperature. In this case, the heat gained or lost is equal to the heat of reaction. By using the given data and substituting into the equation, we can solve for ΔH.

First, we need to determine the mass of the solution. The volume of the solution is 99.5 mL, and assuming a density of 1 g/mL, the mass is 99.5 g.

Next, we can calculate ΔT by subtracting the initial temperature (20.3 °C) from the final temperature (22.1 °C), which is equal to 1.8 °C.

Finally, we can substitute the values into the equation: ΔH = q/(n mol), where n is the number of moles of metal oxide. The mass of the metal oxide is 0.782 g, and assuming a molar mass of metal oxide is M, we can calculate n = (0.782 g/M).