Catalyst:1. If you have 2000 g of water and you heat

it up from 10 oC to 70 oC, then what is the total heat produced in this process? The specific heat of water is 4.18 J/(g x oC).

2. If 980,000 J of energy are added to 6200 g of water at 291 K, what will the final temperature of the water be? The specific heat of water is 4.18 J/(g x oC)

End

Why did you choose the choice that you did? Why do you think it would be better to be burned by one then the other?

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.

There is a large amount of energy that is required to change a solid into a liquid and a liquid into a gas (and vice versa)

ΔHfusion = Energy to change solid to a liquid. ΔHvaporization = Energy to change liquid to a gas. ΔHfreezing = Energy to change liquid to a solid ΔHcondensation = Energy to change gas to a liquid

We can calculate the amount of energy that is necessary to convert a substance from one phase to another

Latent Heat – The energy absorbed as a substance changes phases

ΔH of vaporization/condensation

ΔH of fusion/freezing

Latent Heats

m = mass of compound ΔH = Enthalpy values for phase

changes (constants)

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

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

You have an ice cube of H2O that weighs 2000 kg and you melt it to liquid. How much energy does that require? The ΔHfusion is 334 kJ/kg.

Begin working on your “Homework 7.3” There will be an exit slip after this

activity

Rate yourself 1 – 4 on LTs 7.7

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)

Using your exit slip score, re-rate yourself on LTs 7.7

Test Tuesday!