Final answer:
To determine the enthalpy change (ΔHrxn) for the reaction between AgNO3 and HCl, the total heat absorbed by the solution is calculated using the mass, specific heat capacity, and temperature change. The result is -338.58 J, which does not match with any of the given answer choices, suggesting a recalibration may be needed.
Step-by-step explanation:
To calculate the enthalpy change (ΔHrxn) for the reaction when 50.0 mL of 0.100 M AgNO3 is combined with 50.0 mL of 0.100 M HCl in a coffee-cup calorimeter, we use the formula
q = m × c × ΔT
where
- q is the amount of heat exchanged,
- m is the mass of the solution,
- c is the specific heat capacity of the solution, and
- ΔT is the change in temperature.
Since we are told to use a density of 1.00 g/mL for the solution and that the specific heat capacity, c, is 4.18 J/(g°C), we can calculate the mass by adding the volumes of both solutions:
mass (m) = 50.0 mL + 50.0 mL = 100.0 mL = 100.0 g
The change in temperature (ΔT) is the final temperature minus the initial temperature:
ΔT = 24.21 °C - 23.40 °C = 0.81 °C
Now we can calculate q:
q = 100.0 g × 4.18 J/(g°C) × 0.81 °C = 338.58 J
Since the reaction occurs in an isolated calorimeter, this heat is equal to the ΔHrxn, but with the opposite sign because it is an exothermic reaction. Thus:
ΔHrxn = -q = -338.58 J
However, none of the provided answers (-209 J, -418 J, -836 J, or -1672 J) exactly match this result, indicating there might be a miscalculation or a difference in precision. Double-checking calculations or considering significant figures might be necessary to match one of the given answers.