3. Some ionic compounds are hydrates - solid compounds to which is bound a specific percentage of
water. Some hydrates melt when heated and release energy when they solidify. For example, at
32°C, liquid Glauber's salt - sodium sulphatedecahydrate, Na2SO4. 10H2O(l) - solidifies and releases
78.0kJ/mol of energy. Calculate the enthalpy change when 2.50kg of Glauber's salt enters the solid
state? (ans: -605kJ]

7. using your knowledge of colligative properties explain whether sodium chloride or calcium chloride would be a more effective substance to melt the ice on a slick sidewalk. use 3 – 4 sentences in your explanation. 8. when a 2.5 mol of sugar (c12h22o11) are added to a certain amount of water the boiling point is raised by 1 celsius degree. if 2.5 mol of aluminum nitrate is added to the same amount of water, by how much will the boiling point be changed? show all calculations leading to your answer or use 3 – 4 sentences to explain your answer. 9. if 5.40 kcal of heat is added to 1.00 kg of water at 100⁰c, how much steam at 100⁰c is produced? show all calculations leading to an answer. 10. the freezing of water at 0⁰c can be represented as follows: h2o (l) ↔ h2o(s) the density of liquid water is 1.00 g/cm3. the density of ice is 0.92 g/cm3. in 3 – 4 sentences explain why applying pressure causes ice to melt.