General, Organic, and Biological Chemistry Fourth Edition Karen Timberlake 2.2 Temperature Chapter 2 Energy and Matter © 2013 Pearson Education, Inc. Lectures

© 2013 Pearson Education, Inc. Chapter 2, Section 2 2 Temperature Scales Temperature scales  are Fahrenheit, Celsius, and Kelvin.  have reference points for the boiling and freezing points of water. In science, temperature is measured in Celsius ( o C) units.

© 2013 Pearson Education, Inc. Chapter 2, Section 2 3 A Comparison of Temperatures

© 2013 Pearson Education, Inc. Chapter 2, Section What is the temperature of freezing water? A. 0  F B. 0  C C. 0 K 2. What is the temperature of boiling water? A. 100  F B. 32  F C. 373 K 3. How many Celsius units are between the boiling and freezing points of water? A. 100B. 180C. 273 Learning Check

© 2013 Pearson Education, Inc. Chapter 2, Section What is the temperature of freezing water? B. 0  C 2. What is the temperature of boiling water? C. 373 K 3. How many Celsius units are between the boiling and freezing points of water? A. 100 Solution

© 2013 Pearson Education, Inc. Chapter 2, Section 2 6  On the Fahrenheit scale, there are 180  F between the freezing and boiling points, and on the Celsius scale, there are = 100  C  In the formula for the Fahrenheit temperature, adding 32 adjusts the zero point of water from 0  C to 32  F. Celsius to Fahrenheit Formula

© 2013 Pearson Education, Inc. Chapter 2, Section 2 7  T C is obtained by rearranging the equation for T F.  Subtract 32 from both sides.  Divide by 1.8. Fahrenheit to Celsius Formula

© 2013 Pearson Education, Inc. Chapter 2, Section 2 8 Kelvin Scale  The coldest temperature possible is − o C, which is called absolute zero.  The Kelvin scale is based on absolute zero.  To convert between Kelvin and Celsius: T K = T C + 273

© 2013 Pearson Education, Inc. Chapter 2, Section 2 9 Temperature Comparisons

© 2013 Pearson Education, Inc. Chapter 2, Section 2 10 Kelvin – Celsius – Fahrenheit

© 2013 Pearson Education, Inc. Chapter 2, Section 2 11 Chemistry Link to Health Oral body temperatures vary.  Normal is 37.0  C.  Temperatures of 36.1  C are common in the morning and can climb to a high of 37.2  C between 6 P.M. and 10 P.M. Temperatures above 37.2  C for a person at rest are usually an indication of disease.

© 2013 Pearson Education, Inc. Chapter 2, Section 2 12 Solving a Temperature Problem

© 2013 Pearson Education, Inc. Chapter 2, Section 2 13 Solving a Temperature Problem A person with hypothermia has a body temperature of 34.8  C. What is that temperature in  F? Step 1 State the given and needed quantities. Analyze the Problem. Step 2 Write a temperature equation. GivenNeed 34.8  CTemperature in  F

© 2013 Pearson Education, Inc. Chapter 2, Section 2 14 Solving a Temperature Problem A person with hypothermia has a body temperature of 34.8  C. What is that temperature in  F? Step 3 Substitute in the known values and calculate the new temperature. Answer to the tenths place.

© 2013 Pearson Education, Inc. Chapter 2, Section 2 15 Learning Check A pepperoni pizza is baked at 455  F. What temperature is needed on the Celsius scale? A. 423  C B. 235  C C. 221  C

© 2013 Pearson Education, Inc. Chapter 2, Section 2 16 A pepperoni pizza is baked at 455  F. What temperature is needed on the Celsius scale? Step 1 State the given and needed quantities. Analyze the Problem. Step 2 Write a temperature equation Solution GivenNeed 455  F C C

© 2013 Pearson Education, Inc. Chapter 2, Section 2 17 A pepperoni pizza is baked at 455  F. What temperature is needed on the Celsius scale? Step 3 Substitute in the known values and calculate the new temperature. Answer: B Answer to ones place. Solution

© 2013 Pearson Education, Inc. Chapter 2, Section 2 18 On a cold winter day, the temperature is –15  C. What is the temperature in  F? A. 19  F B. 59  F C. 5  F Learning Check

© 2013 Pearson Education, Inc. Chapter 2, Section 2 19 On a cold winter day, the temperature is –15  C. What is the temperature in  F? Step 1 State the given and needed quantities. Analyze the Problem. Step 2 Write a temperature equation. Solution GivenNeed –15  CTemperature in  F

© 2013 Pearson Education, Inc. Chapter 2, Section 2 20 On a cold winter day, the temperature is –15  C. What is the temperature in  F? Step 3 Substitute in the known values and calculate the new temperature. Answer to ones place. Note: Use the “change sign” key on a calculator to enter. the negative (–) sign. Solution

© 2013 Pearson Education, Inc. Chapter 2, Section 2 21 What is normal body temperature of 37  C in Kelvin? A. 236 K B. 310 K C. 342 K Learning Check

© 2013 Pearson Education, Inc. Chapter 2, Section 2 22 What is normal body temperature of 37  C in Kelvin? Step 1 State the given and needed quantities. Analyze the Problem. Step 2 Write a temperature equation. Solution GivenNeed 37  C Temperature in K

© 2013 Pearson Education, Inc. Chapter 2, Section 2 23 What is normal body temperature of 37  C in Kelvin? Step 3 Substitute in the known values and calculate the new temperature. Answer: B Answer to the ones place. Solution