1. © 2013 Pearson Education, Inc. Chapter 7, Section 6 General, Organic, and Biological Chemistry Fourth Edition Karen Timberlake 7.6 The Combined Gas Law Chapter 7 Gases © 2013 Pearson Education, Inc. Lectures

2. © 2013 Pearson Education, Inc. Chapter 7, Section 6 Combined Gas Law 2 The combined gas law uses Boyle’s Law, Charles’s Law, and Gay-Lussac’s Law (n is constant).

3. © 2013 Pearson Education, Inc. Chapter 7, Section 6 Combined Gas Law By using the combined gas law, we can derive any of the gas laws by omitting those properties that do not change. 3

4. © 2013 Pearson Education, Inc. Chapter 7, Section 6 A 0.180 L sample of gas has a pressure of 0.800 atm at 29 °C. At what temperature (°C) will the gas have a volume of 90.0 mL and a pressure of 3.20 atm (n constant)? Step 1 Organize the data in a table of initial and final conditions. Analyze the Problem. Using the Combined Gas Law Conditions 1Conditions 2 P 1 = 0.800 atmP 2 = 3.20 atm V 1 = 0.180 LV 2 = 90.0 mL= 0.0900 L T 1 = 29 °C + 273 = 302 KT 2 = ? 4

5. © 2013 Pearson Education, Inc. Chapter 7, Section 6 A 0.180 L sample of gas has a pressure of 0.800 atm at 29 °C. At what temperature (°C) will the gas have a volume of 90.0 mL and a pressure of 3.20 atm (n constant)? Step 2 Rearrange the gas law equation to solve for the unknown quantity. Using the Combined Gas Law 5

6. © 2013 Pearson Education, Inc. Chapter 7, Section 6 A 0.180 L sample of gas has a pressure of 0.800 atm at 29 °C. At what temperature (°C) will the gas have a volume of 90.0 mL and a pressure of 3.20 atm (n constant)? Step 3 Substitute values to solve for unknown. Using the Combined Gas Law

7. © 2013 Pearson Education, Inc. Chapter 7, Section 6 A gas has a volume of 675 mL at 35 °C and 0.850 atm pressure. What is the volume (mL) of the gas at −95 °C and a pressure of 802 mmHg (n constant)? Learning Check 7

8. © 2013 Pearson Education, Inc. Chapter 7, Section 6 A gas has a volume of 675 mL at 35 °C and 0.850 atm pressure. What is the volume (mL) of the gas at −95 °C and a pressure of 802 mmHg (n constant)? Step 1 Organize the data in a table of initial and final conditions. Analyze the Problem. Solution 8

9. © 2013 Pearson Education, Inc. Chapter 7, Section 6 A gas has a volume of 675 mL at 35 °C and 0.850 atm pressure. What is the volume (mL) of the gas at −95 °C and a pressure of 802 mmHg (n constant)? Step 2 Rearrange the gas law equation to solve for the unknown quantity. Solution 9

10. © 2013 Pearson Education, Inc. Chapter 7, Section 6 A gas has a volume of 675 mL at 35 °C and 0.850 atm pressure. What is the volume (mL) of the gas at −95 °C and a pressure of 802 mmHg (n constant)? Step 3 Substitute values into the gas law equation and calculate. Solution 10