2. Catalyst 1.When solid ice is being continuously heated, at what point does it stop gaining kinetic energy? What is this called? When does it start gaining kinetic energy again? End

3. 100 o C Water Burn100 o C Steam Burn

4. Justify – TPS Why is it worse to be burnt by 100 o C steam than 100 o C water? Justify your answer with Word Wall vocab!

5. Lecture 7.5 – Latent Heats

6. Today’s Learning Target 7.7 – I can use the latent heat of phase change to calculate the amount of energy that is released or absorbed during a change of phase.

7. What are Latent Heats?

8. I. ΔH fusion and ΔH vaporization There is energy required to change phases ΔH fusion = Energy to change solid to a liquid. ΔH vaporization = Energy to change liquid to a gas. ΔH freezing = Energy to change liquid to a solid ΔH condensation = Energy to change gas to a liquid

9. II. Latent Heat Can calculate the amount of energy needed to convert a substance from one phase to another Latent Heat – The energy absorbed as a substance changes phases

10. ΔH of vaporization/condensat ion ΔH of fusion/freezing Latent Heats

11. How do you calculate latent heats?

12. I. Equation for Latent Heat m = mass of compound ΔH = Enthalpy values for phase changes (constants) Easy way to remember: Q equals maH! (The delta kinda looks like an A!)

13. Class Example You have a 2000 kg of ethanol. Calculate the energy you would need to turn solid aluminum into liquid. The ΔH fusion is 109 kJ/kg.

14. Table Talk You have 6342 kg of mercury. How much energy would be required to take mercury from liquid to a gas? The ΔH vaporization is 294 kJ/kg

15. Stop and Jot You have an ice cube of H 2 O that weighs 2000 kg and you melt it to liquid. How much energy does that require? The ΔH fusion is 334 kJ/kg.

16. SUMMARIZE

17. Checklist Manifesto! How do I know which equation to use?  Does it have specific heat?  Then use calorimetry!  Does it give you ΔH or ΔT  If ΔH then use q = mΔH  If ΔT then use q = m x C p x ΔT  Box the one it’s asking you to find!  Plug in the right numbers and solve!

18. Connect 4

19. Begin working on your “Homework 7.4” There will be an exit slip after this activity Work Time

20. Learning Log Assessment Rate yourself 1 – 4 on LTs 7.1-7.7

21. 1. You have 2000 g of water that is heated from 25 C to 100 C. What is the heat absorbed by this process. The specific heat of water is 4.184 J/(gxC) Exit Slip

22. Learning Log Assessment Rate yourself 1 – 4 on LTs 7.7

24. Test Next! Closing Time