Question

Sure! Here is a question for the student to solve:What is the enthalpy change for the dissolution of 10 grams of potassium nitrate (KNO3) in 100 grams of water at 25°C? Given the molar enthalpy of dissolution for KNO3 to be -34.01 kJ/mol.

Answer 1

To calculate the enthalpy change for the dissolution of 10 grams of potassium nitrate  KNO3  in 100 grams of water at 25C, we need to follow these steps:1. Determine the number of moles of KNO3.2. Multiply the moles of KNO3 by the molar enthalpy of dissolution.Step 1: Determine the number of moles of KNO3The molar mass of KNO3 = 39.10 g/mol  K  + 14.01 g/mol  N  + 3 * 16.00 g/mol  O  = 101.11 g/molNow, we can calculate the number of moles of KNO3:moles = mass / molar massmoles = 10 g / 101.11 g/mol = 0.0989 molStep 2: Multiply the moles of KNO3 by the molar enthalpy of dissolutionEnthalpy change = moles * molar enthalpy of dissolutionEnthalpy change = 0.0989 mol *  -34.01 kJ/mol  = -3.365 kJThe enthalpy change for the dissolution of 10 grams of potassium nitrate  KNO3  in 100 grams of water at 25C is approximately -3.365 kJ.