Mr. Quinn & Ms. Tom March 5, 2014 Aim: How much energy is required to melt of boil water? Do Now: Look at the heating curve to the right. Does melting or boiling require more energy? How can you tell?

Two Types of Reactions Phase changes require energy called LATENT HEAT. To melt we use the “heat of fusion,” and to boil we use the “heat of vaporization.” For melting: Q = Heat of Fusion x mass For boiling: Q = Heat of Vaporization x mass

Let’s Try It Out! What is the amount of heat energy required to completely melt 10 g of water at 0 °C? Q = Heat of Fusion x mass Q = Heat of Fusion = mass = Hints: What are you looking for? Where do you find “Heat of Fusion?”

Let’s Try It Out! What is the amount of heat energy required to completely vaporize 15 g of water at its boiling point? Q = Heat of Vaporization x mass Q = Heat of Vaporization= mass = Hints: What are you looking for? Where do you find “Heat of Vaporization?”

Let’s Try It Out! What is the amount of heat energy required to completely vaporize 23 g of water at 100 °C? Q = Heat of x mass Q = Heat of = mass = Hints: What are you looking for? Which heat are you looking for?

Your Turn!

What is the amount of heat energy required to completely melt 6 g of water at 0 °C? Q = Heat of Fusion x mass Q = Heat of Fusion = mass = Hints: What are you looking for? Where do you find “Heat of Fusion?”

Your Turn! What is the amount of heat energy required to completely vaporize 36 g of water at its boiling point? Q = Heat of Vaporization x mass Q = Heat of Vaporization= mass = Hints: What are you looking for? Where do you find “Heat of Vaporization?”

Let’s Try It Out! What is the amount of heat energy required to completely boil 17 g of water at 100 °C? Q = Heat of x mass Q = Heat of = mass = Hints: What are you looking for? Where do you find “Heat of Vaporization?”

Let’s Try It Out! What is the amount of heat energy required to completely melt 81 g of water at its melting point? Q = Heat of = mass =