0 votes
28 views
in ThermoChemistry by (350 points)
What is the amount of heat released when 5 grams of NaCl is crystallized from its aqueous solution at 25°C, and the final temperature of the solution is -5°C? (Given: Heat of crystallization of NaCl = -3.92 kJ/mol)

1 Answer

0 votes
by (290 points)
First, we need to determine the number of moles of NaCl in 5 grams. The molar mass of NaCl is 58.44 g/mol  22.99 g/mol for Na and 35.45 g/mol for Cl .Number of moles =  mass of NaCl  /  molar mass of NaCl Number of moles = 5 g / 58.44 g/mol = 0.0856 molNow, we can calculate the heat released during the crystallization process using the given heat of crystallization.Heat released =  number of moles    heat of crystallization Heat released = 0.0856 mol   -3.92 kJ/mol  = -0.3355 kJThe negative sign indicates that heat is released during the crystallization process. However, this is only the heat released during the crystallization. We also need to consider the heat released when the solution cools down from 25C to -5C.To do this, we need to know the specific heat capacity of the solution and its mass. Unfortunately, this information is not provided in the problem. If it were provided, we could calculate the heat released during the cooling process using the formula:Heat released =  mass of solution    specific heat capacity    change in temperature Without this information, we cannot determine the total amount of heat released when the NaCl crystallizes and the solution cools down to -5C.

Related questions

Welcome to Sarvan Science Q&A, where you can ask questions and receive answers from other members of the community.
...