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**Problem**: Potassium nitrate, KNO3, has a molar mass of 101.1 g/mol. In a constant-pressure calorimeter, 32.3 g of KNO3 is dissolved in 243 g of water at 23.00 °C.KNO3(s)+H2O(aq) → KOH(aq)+HNO3(aq)The temperature of the resulting solution decreases to 17.90 °C. Assume the resulting solution has the same specific heat as water, 4.184 J/(g·°C), and that there is negligible heat loss to the surroundings.1. How much heat was released by the solution?2. What is the enthalpy of the reaction?

###### FREE Expert Solution

###### FREE Expert Solution

**Calculate the amount of heat released in the reaction**

$\overline{){{\mathbf{q}}}_{{\mathbf{system}}}{\mathbf{}}{\mathbf{=}}{\mathbf{}}{{\mathbf{q}}}_{{\mathbf{solution}}}{\mathbf{}}{\mathbf{+}}{\mathbf{}}{{\mathbf{q}}}_{{\mathbf{reaction}}}}$

• Since no heat is lost to the surroundings: q_{system} = 0

**The heat (q) of the solution can be calculated using:**

$\overline{){{\mathbf{q}}}_{\mathbf{sol}\mathbf{\u2019}\mathbf{n}}{\mathbf{}}{\mathbf{=}}{\mathbf{}}{\mathbf{mc}}{\mathbf{\u2206}}{\mathbf{T}}}$

Where

m is the mass of the solution

c is the specific heat of water (4.1801 J/g-k)

∆T is the change in temperature (T_{final} - T_{initial})

###### Problem Details

Potassium nitrate, KNO_{3}, has a molar mass of 101.1 g/mol. In a constant-pressure calorimeter, 32.3 g of KNO_{3} is dissolved in 243 g of water at 23.00 °C.

KNO_{3}(s)+H_{2}O(aq) → KOH(aq)+HNO_{3}(aq)

The temperature of the resulting solution decreases to 17.90 °C. Assume the resulting solution has the same specific heat as water, 4.184 J/(g·°C), and that there is negligible heat loss to the surroundings.

1. How much heat was released by the solution?

2. What is the enthalpy of the reaction?

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