Question

Calculate the standard enthalpy change for the dissolution of 5 grams of ammonium chloride (NH4Cl) in water, given that the molar enthalpy of dissolution of NH4Cl is -340.0 kJ/mol. The molar mass of NH4Cl is 53.49 g/mol and the density of water is 1.00 g/mL.

Answer 1

To calculate the standard enthalpy change for the dissolution of 5 grams of ammonium chloride  NH4Cl  in water, we first need to determine the number of moles of NH4Cl in 5 grams.Number of moles = mass / molar massNumber of moles = 5 g / 53.49 g/mol = 0.0935 molNow that we have the number of moles, we can calculate the enthalpy change using the molar enthalpy of dissolution.Enthalpy change = number of moles  molar enthalpy of dissolutionEnthalpy change = 0.0935 mol   -340.0 kJ/mol  = -31.79 kJThe standard enthalpy change for the dissolution of 5 grams of ammonium chloride in water is -31.79 kJ.