CALORIMETRY AND HEAT CONTENT CHANGES

AIM:

What is heat and how do we measure heat changes?

Objectives:

1. SWBAT describe the difference between temperature and heat.
2. SWBAT list the factors that influence the heat change of an object.
3. SWBAT describe how to setup and conduct a calorimetric experiment to determine the specific heat capacity of a metal.
4. SWBAT perform all the calculations to determine the specific heat capacity of a metal from the data obtained in a calorimetric experiment.

Homework:

Read Chapter 18 pgs 715 – 728 | Complete Practice Problems (8-10) page 718 & (11-15) page 728 .

Key words:

• heat, temperature, thermometer, degree Celsius, mass, average kinetic energy, total kinetic energy, heat flow, calorimetry, calorimeter, delta, specifiic heat capacity, heat quantity.

Resources:

• hot plate, heating vessel with water/ sample metals (lead, iron, copper, & aluminum), balance, calorimeter, 2 thermometers, chalkboard, & lab handouts with data sheets for each student.

Motivation: Do Now:

Describe how the amount of heat in a bathtub full of water at 100^oC is alike and is different from a coffee cup filled with water at 100^oC.

Development:

1. Using the motivation example, explain how temperature and heat are different.
2. Develop the heat change equation on the board by listin the factors the students come up with that affect the amount of heat change in an object (disregard latent heat considerations at this time)
3. Perform the calorimetry exercise with each of the four metals listed above & ask questions concerning each step. (Heat flow, temperature of things in the hot bath, etc.)
4. Have the students calculate the quantity of heat transferred from each of the hot metals to the water in each calorimetry exercise.
5. Have the students calculate the specific heat capacity of each metal using their data and the results of their calculations in step 4.

Medial Summary:

1. Have the students describe the difference between heat and temperature
2. Have the students explain why the fluid in a thermometer rises as the temperature increases.
3. Have the students describe the process of heat flow and how it relates to kinetic energy.
4. Have the students explain why cold doesn’t flow.
5. Have the students describe a human event that simulates the process of heat flow.

Application:

1. Have the students calculate how much heat the 2 250 L of water in a standard fire truck tank can absorb while undergoing a temperature change from 23^oC to 99^oC.

Summary:

1. Have the students list the factors that influence the amount of heat change a sample undergoes.
2. Have the students explain where they can find the specific heat capacity value for water on their Regents Reference and where they can find the heat equation on the reference.