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Monday and Tuesday April 16 and 17. Chapter 10: Thermodynamics. What is energy? Is there a difference between heat and temperature?. Heat Energy flow caused by a temperature difference Measured in J or cal 1 cal = 4.184 J. Temperature Measure of random motion of a substance

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Monday and tuesday april 16 and 17

Monday and TuesdayApril 16 and 17


Chapter 10 thermodynamics

Chapter 10:Thermodynamics

What is energy?

Is there a difference between heat and temperature?


Heat

Energy flow caused by a temperature difference

Measured in J or cal

1 cal = 4.184 J

Temperature

Measure of random motion of a substance

Measured in ̊C, ̊F, or K


Calculations
Calculations

  • Convert temperature

  • Change in temperature

  • Convert to grams of a substance

  • Q=SM∆T


Converting t f to c
Converting T ( ̊F to ̊C)

Fahrenheit to Celsius

T ( ̊C) = ( T(°F) – 32) x (5/9)

Ex: Convert 65 ̊F to ̊C

T ( ̊C) = ( T(°F) – 32) x (5/9)

T ( ̊C) = ( 65 °F – 32) x (5/9)

T ( ̊C) = 18. ̊C


Change in t t
Change in T (∆T)

∆T = T final – T initial

Ex: If a cup of boiling water is left on the counter until it comes to room temperature (20 ̊C), what is the change in temperature?

∆T = T final – T initial

∆T = 20 ̊C – 100 ̊C

∆T = -80 ̊C


Convert to grams from mol
Convert to grams (from mol)

Convert 6.00 mol of H2O to grams.

108. g H20


Q sm t
Q = SM∆T

Q = Energy (heat) required in Joules

S = specific heat capacity in J/g̊C

M = mass of the sample in grams

∆T = change in temperature in ̊C


Specific Heat Capacity

The amount of energy required to raise the temperature of one gram of a substance by one degree Celsius.


Heat transfer
Heat transfer

How can people walk on hot coals?

http://www.youtube.com/watch?v=3ToRsSYSkbY


Specific Heat Capacity

The amount of energy required to raise the temperature of one gram of a substance by one degree Celsius.


Q sm t1
Q = SM∆T

How much energy is needed to warm 7.40 g of water from 17.0 ̊C to 35.0 ̊C?

Q = want

S = 4.184 J/g̊C (from table)

M = 7.40 g

∆T = 35.0 ̊C – 17.0 ̊C= 18.0 ̊C


Recommended reading
Recommended Reading

Homework:

Thermo WS 1

10.2 (pg 291 – 292)

10.5 (pg 294 – 300)

Practice Problems

Pg 318 - 320 # 6-10, 22-28, 49-58

Rewrites are due Friday, 4/20

Extra credit assignment due 5/11


Wednesday and thursday april 18 and 19
Wednesday and ThursdayApril 18 and 19


Warm up
Warm UP

How much energy is needed to warm 3.60 g of lead from 17.0 ̊C to 35.0 ̊C?

Q = want

S = 0.128 J/g̊C (from table)

M = 3.60 g

∆T = 35.0 ̊C – 17.0 ̊C= 18.0 ̊C




Practice problem
Practice Problem

How much energy is introduced in to 1.0 kg of ice at -20.0°C, to turn it into steam at 110.0°C?

Q = want

S = 2.03 J/g̊C (from table)

M = 1.0 x 103 g

∆T = 110.0 ̊C – -20.0 ̊C= 130.0 ̊C


Calorimeter
Calorimeter

Calorimeter is a heat measuring device.

The calorimeter is generally used to measure the amount of heat energy transferred during a reaction.

Using this information, one can calculate the specific heat of a substance or other heat related information.

Stirrer

Thermometer

Water

Metal pieces

Insulated container


Calorimeter1
Calorimeter

A closed system in which energy is maintained.

-(Q 1) = Q 2


Calorimeter2
Calorimeter

If a 30.0 g block of iron is put into the calorimeter and -9.87 J of energy is released, how much energy does the water take on?


Practice problems
Practice Problems

A sample of aluminum (0.895 J/g °C )at 75.0°C was placed in a calorimeter containing 25.0 grams of water at 20.0°C. The temperature stopped changing at 29.4°C. What is the mass of the sample?

-(Q 1) = Q 2

-(SmetalMmetal∆Tmetal )= SwaterMwater∆Twater


Practice problems1
Practice Problems

A 4.57 g sample of metal is heated to 57.8 ̊C and placed in 150. mL of water that is at 20.0 ̊C. The temperature of the water increases to 40.0 ̊C. What is the specific heat capacity of the metal?

-(Q 1) = Q 2

-(SmetalMmetal∆Tmetal )= SwaterMwater∆Twater


Practice problems2
Practice Problems

A 8.13 g sample of iron is heated to 45.4 ̊C and placed in 400. mL of water that is at 23.0 ̊C. What will the final temperature?

-(Q 1) = Q 2

-(SmetalMmetal∆Tmetal )= SwaterMwater∆Twater


Practice problems3
Practice Problems

A 7.01 kg sample of iron is heated to 69.4 ̊C and placed in 6.71 L of water. The final temperature of the water is 39.8 ̊C. What is the initial temperature of the water?

-(Q 1) = Q 2

-(SmetalMmetal∆Tmetal )= SwaterMwater∆Twater


Homework and reminders
Homework and Reminders

Homework:

Thermo WS 2

Reminders:

Rewrites are due FRIDAY, 4/20

Extra credit due 5/11


Friday april 20
FridayApril 20


Rewrites due
REWRITES DUE

If you rewrote your Lab 3.21 for proficiency, turn in the highlighted rewrite and the original paper to the turn in bin.


Warm up1
Warm Up

If 150.0 grams of iron at 95.0 °C, is placed in an insulated container containing 500.0 mL of water at 25.0 °C, and both are allowed to come to the same temperature, what will that final temperature be?




Quiz time
Quiz Time

Clear desk except a pencil and calculator


Thermodynamics lab
Thermodynamics Lab

Purpose: Determine the specific heat capacity of an unknown metal and identify the metal.

Complete the prelab

assignment

BEFORE class.

Dress appropriately

for lab


Notes for the lab
Notes for the lab

  • Don’t poke the thermometer through the cups

  • Put metal in water and cover as quickly as possible


Homework and reminders1
Homework and Reminders

Homework:

Thermo WS 3

Thermo prelab

Reminders:

Rewrites are due FRIDAY, 4/20

No exceptions


Monday and tuesday april 23 and 24
Monday and TuesdayApril 23 and 24


Warm up2
Warm Up

In a calorimeter 187 mL of 18.9 ̊C water is mixed with a 4.32 g block of 92.0 ̊F granite. What will the final temperature be?




Lab time
Lab Time

  • Don’t poke the thermometer through the cups

  • Put metal in water and cover as quickly as possible


Done in lab
Done in lab?

◦Work on write up

Title, purpose, data tables, calculations, analysis

If you finish the lab turn it in to the turn in bin, if not it is your homework

◦Work on practice test if you finish the lab


Reminders
Reminders

Homework:

Thermo Lab Write Up

GeneralReminders:

Extra Credit due 5/11

Thermodynamics Test 4/25 and 4/26


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