Last modified: Thu 02/26/2009 10:26:07 am
CHEM 1314 Fall 2008 ACA11

Oklahoma State University

This is ACA # 11, our eleventh ACA of the Fall semester. It is OK to use your textbook or lecture notes from class, but if you can answers the questions without it that is OK too.

Do not press the RETURN or ENTER key while you are answering these questions. Your browser will interpret either the same as clicking on the Submit key.

Answer all of the questions below. If you do not know an answer enter CNA. However, it will help me the most if you answer each question with your best intuition/idea about what would be a reasonable answer.


First Name:

Last Name:

Laboratory Section:

1. In the table below are the specific heats for aluminum, gold and iron.

Substance Specific Heat (J g-1 °C-1)
Al

0.90

Au

0.13

Fe

0.45

Each sample of aluminum, gold and iron has the same mass and is at the same initial temperature. If the same amount of heat is added to each sample, using a bunsen burner, predict which substance will have the higher final temperature.

Substance (aluminum, gold or iron)

Briefy explain why you picked that substance

2. Consider the following: 100. grams of iron solid at 100 °C is added to 100. grams of water (specific heat of water is 4.18 J g-1 °C-1) at 25 °C.

a) After placing the sample of iron into the sample of water will the final temperature of the system (the iron and water mixture) be closer to the initial temperature of the iron, or the initial temperature of the water?

b) Support your response with a brief explanation.

3. How much heat (in joules) is required to change the temperature of 200.0 grams of H2O from 23.2 °C to 87.3 °C? (Remember the specific heat of H2O(l) is 4.184 J g-1 °C-1 and that q(heat) = mass*specific heat*T)

joules

4. How much heat (in joules) is required to change the temperature of 200.0 grams of Cu from 23.2 °C to 87.3 °C? (Remember the specific heat of Cu(s) is 0.384 J g-1 °C-1.)
joules

5. Calculate the final temperature when 25.0 grams of H2O at 23.5 °C are added to 27.0 grams of H2O at 63.5 °C.
°C

6. Calculate the final temperature when a 58.50 grams sample of copper, initially at a temperature of 98.5 °C is added to 205.0 grams of H2O at 24.0 °C.
°C

7. Is there anything about the questions that you feel you do not understand? List your concerns/questions.

8. If there is one question you would like to have answered in lecture, what would that question be?