2.  If temperature of water goes down, the reaction is taking energy from the water  Therefore, the reaction is ENDOTHERMIC  If the temperature of the water goes up, the reaction is releasing energy to the water  Therefore, the reaction is EXOTHERMIC

3. Decide whether the following processes are exothermic or endothermic: 1. Freezing of water 2. Vaporization of water 3. NaOH is dissolved in water and the temperature of water rises 4. NH 4 Cl is dissolved in water and temperature of water goes down

4. Decide whether the following processes are exothermic or endothermic: 1. CaCl 2(s)  Ca +2 + 2Cl - + 81.3 kJ 2. N 2 + 3H 2  2NH 3 ΔH = -80.8 kJ 3. 2 H 2(g) + O 2(g)  2 H 2 O (l) ΔH = -571.6 kJ 4. 67.6 kJ + N 2(g) + 2 O 2(g)  2 NO 2(g)

5. 1. What is the definition of heat? 2. The SI unit of heat and energy is __________. 3. The energy always flows from a __________ object to a ____________ object. 4. What is the definition of temperature?

6. 1. Exothermic reactions ____________ energy. 2. Endothermic reactions ____________ energy. 3. Breaking bonds ____________ energy. 4. Forming bonds _______________ energy.

7. Mass of metal40.0 g Initial temperature of metal 5.0 o C Mass of water in calorimeter 20.0 g Initial temperature of water 30.0 o C Final temperature of water/metal 20.0 o C Specific heat of water 4.184 J/g∙ o C 1. According to the data given, the metal is __________ energy and the water is ____________ energy (losing/gaining) 2. How much heat was transferred from the water? 3. How much heat was transferred to the metal? 4. What is the specific heat capacity of the metal?

8. 1. CaCl 2(s)  Ca +2 + 2Cl - + 81.3 kJ If 7.0 mol of Cl - are produced, how many kJ of energy are produced? 2. N 2 + 3H 2  2NH 3 ΔH = -80.8 kJ If 7.0 mol of NH 3 are produced, how many kJ of energy are produced? 3. 2 H 2(g) + O 2(g)  2 H 2 O (l) ΔH = -571.6 kJ If 7.0 mol of H 2 O are produced, how many kJ of energy are produced? 4. 67.6 kJ + N 2(g) + 2 O 2(g)  2 NO 2(g) If 7.0 mol of NO 2 are produced, how many kJ of energy are absorbed?

9.  1. What letter represents the solid phase?  2. What letter represents the gas phase?  3. Going from a to b (blue arrow) represents what phase change?  4. Going from C to D (green arrow) represents what phase change?

10. 1. Where do ALL three phases exist in equilibrium? 2. What phase exists at 15°C and 5 mmHg? 3. You are at 0°C and 8 mmHg. What must be done cause the solid to sublime? 4. You are at 5°C and 10 mmHg. What must be done to freeze the liquid?

11. 1. Which segment contains both vapor & liquid? 2. Which segment contains solid only? 3. For which segments do you need to use Q = mcΔT? 4. For which segments do you need to use the molar heat of fusion and the molar heat of vaporization?

12. 1. & 2. Calculate the energy needed to melt 50.0 g of ice at 0°C. The molar heat of fusion is 6.07 kJ/mol. 3 & 4: Calculate the energy needed to vaporize 100.0 g of water at 100°C. The molar heat of vaporization is 40.7 kJ/mol

13. How much heat is required to heat 50.0g of water from at temperature of -20°C to 50°C? 1. Calculate the heat for the first segment. 2. Calculate the heat for the second segment 3. Calculate the heat for the third segment 4. Calculate the total heat for the heating of the water. Molar heat of fusion = 6.07 kJ/mol Specific heat for solid = 2.06 J/g°C Specific heat for liquid = 4.18 J/g°C

14. 1. What is the specific heat capacity of a metal if it starts at 10°C and is heated to 40°C, has a mass of 5 g and absorbs 60 J of energy? 2. What is the mass of a glass of water if it cools from 80°C to 20°C and releases -6276 J of energy? 3. What is the specific heat capacity of a cotton ball if it starts at 22°C and warms to 30°C, has a mass of 8 g and absorbs 384 J of energy? 4. What is the mass of a chunk of aluminum if it has a specific heat of 0.9 J/g°C, starts at 24°C and ends at 45°C, and absorbs 189 J of energy?