DO NOW: Hand in specific heat lab &answer the following question on “Do Now” sheet:

56 grams of hot copper are added to 140 grams of water in a 92 g aluminum calorimeter causing the temperature of the water to rise from 22.0oC to 29.5oC. What was the initial temperature of the hot copper?

Cwater=4180 J/(kg K) CAl=897 J/(kg K) CCu=385 J/(kg K)

Ti= ?

Q1=(mcDT)water

Q2=(mcDT)Al

Q3=(mcDT)Cu

Q1+Q2+Q3=0

22.0o

C

29.5o

C

140 g water

92 g Al

56 g Cu

Agenda 3.6.2014Describe states of matter

Explore what happens when a substance changes from one state of matter to another.

Label and explain “heating curves”

Use heat of vaporization and heat of fusion to calculate energy absorbed or released when a substance undergoes a change of state.AnnouncementsQuiz tomorrow on Chapter 12.1

HW – 12.1 Review Worksheet

List and Photo of Materials – Extended to Monday (3/10)

State of matter with fixed volume and shape. Molecules are in motion but are tightly packed and maintain their locations relative to neighboring molecules.1. Solid2. Liquid3. Gas4. Plasma

Measure of the average kinetic energy per randomly wiggling particle

1. Heat2. Thermal Energy3. Temperature4. Specific Heat

Measure of the total amount of kinetic energy associated with the random motion of particles plus the total potential energy associated with the intermolecular bonds

1. Heat2. Thermal Energy3. Temperature4. Specific Heat

State of matter that takes on the shape of its container but has a constant volume. Although molecules are tightly packed bonds are continuously changing as they change their locations relative to neighboring molecules.

1. Solid2. Liquid3. Gas4. Plasma

In this state of matter molecules do not form lasting bonds with neighbors and spread out to occupy all the space available. With plenty of extra room between molecules this state of matter can be compressed into a smaller volume.1. Solid2. Liquid3. Gas4. Plasma

At high enough temperatures particles in a gas have enough kinetic energy to knock electrons free from neutral atoms resulting in this “hot soup” of charged ions.1. Solid2. Liquid3. Gas4. Plasma

Heat is added at a uniform rate to a pot of water that starts off at room

temperature. The temperature of the water is shown for the first few

minutes. Sketch what you think the rest of the graph look like if the pot is

left on the stove for 20 minutes

0 2 4 6 8 10 12 14 16 18 200

20

40

60

80

100

120

Time (minutes)

Tem

pera

ture

(oC

)

Take 3 minutes to discuss in small groups what is going on here.

Would the formula Q=mcDT work for the entire 20 minutes? Why or

why not?

0 5 10 15 200

20

40

60

80

100

120

Time (minutes)

Tem

pera

ture

(oC

)

Why does boiling water stay at 100oC

when you continue to add heat?In liquid state molecules are “stuck”

to neighbors by temporary bondsAddition of heat at the boiling point “un-sticks” molecules from neighboring particles WITHOUT increasing kinetic energy.

BIG IDEA – At the boiling point adding heat results in a change of state. As H2O changes from liquid to gas thermal energy increases but temperature stays the same!

Changes of State Phase

Diagram - Water

Melting Point

Boiling Point

DO NOW Take out your homework and answer the following question (3 min).

How much heat is required to raise the temperaure of 1 kg liquid water (C = 4180 J/kg °C) from 0 °C to 100 °C ?

Q = mCwaterΔT

Heating curves

http://www.kentchemistry.com/links/Matter/HeatingCurve.htmHEAT

Heat of fusion (Hf)Amount of heat required to melt 1 kg

at the melting point Heat required to melt something:

Q=mHf

Heat required to freeze something: Q=m(-Hf)

Example: Adding 668 kJ to a block of ice at 0oC causes 2.0 kg to melt. What is the heat of fusion of ice?

Q= 6.68x105 Jm=2.0 kg

Hf= Q/m =3.34x105 J/kg

Heat of Vaporization (Hv)Amount of heat required to change 1 kg of

liquid to a gas at the boiling point. Heat required to vaporize something:

Q=mHv

Heat required to condense something: Q=m(-Hv)

Example: The boiling point of ethanol is 78oC. How much heat must be added to 750 g of ethanol at 78oC to turn it into a gas if Hv=846 kJ/kg ?

m=0.75 kg Hv=846 kJ/kg

Q=mHv=635 kJ

Definition1. Change from solid to

liquid

2. Energy required to convert 1 kg from a solid to liquid at the melting point

3. Liquid phase and gaseous phase can exist in equilibrium

4. Change from liquid to gas

5. Energy required to convert 1 kg from a liquid to a gas at the boiling point.

6. Solid Phase and liquid phase can exist in equililbrium.

TermA. Melting Point

B. Boiling Point

C. Heat of Vaporization

D. Vaporization

E. Melting

F. Heat of Fusion

DO NOW – Have your photo and list of materials ready for me to check and match the definitions with the terms

E

F

B

C

A

D

-40

0

100

130

Tem

pera

ture

of H

20 (°

C)

Heat added Q = mCiceΔT

Q = mCwaterΔT

Q = mCsteamΔT

Q = mHf

Q = mHv

Heating Curve for Water

-400

100

130

Tem

pera

ture

of H

20 (°

C)

Heat added Q = mCiceΔT

Q = mCwaterΔT

Q = mCsteamΔT

Q = mHf

Q = mHv

Heating Curve for Water

Q = mCiceΔT

Q = mHf

Q = mCwaterΔT

Q = mHv

Q = mCsteamΔT

Drawing Heat Diagrams

-40°C

0°C

100°C

130°C

What is the total amount of heat required to raise the temperature 1 kg of water from -40 °C to 20 °C?Cice= 2060 J/kg°C Cwater = 4180 J/kg°CHf = 3.35x105 J/kgQ = mCiceΔT

Q = mHf

Q = mCwaterΔT

-40°C

0°C

20°C

Qtotal = mCiceΔT + mHf + mCwaterΔT

Qtotal = 82400 J + 3.35x105 J + 83600 J

Qtotal = 5.01x105 J

HomeworkChange of State Problems – p. 337 #61, 62, 64