Catalyst 1. As temperature in a chamber decreases, what happens to the pressure inside that chamber? 2. If you increase the pressure inside a balloon, what happens to the balloon’s volume? End

Test Tube and Balloons

Balloon in a Bottle

Balloon in a Bottle What causes the balloon to expand? What happens to air that is trapped in the bottle when you blow into the balloon? Design and draw a modification to the balloon-in-a-bottle that will allow the balloon to inflate. Explain why your design works.

Lecture 6.5 – Combined and Ideal Gas Law

Today’s Focus Question – Why is there more smog in the summer than the winter?

Today’s Learning Targets LT 6.10 – I can calculate the various properties of a gas using the Ideal Gas Law and the Combined Gas Law.

What is the Combined Gas Law?

I. Gas Law Review Boyle’s Law (inverse relationship): PiVi=PfVf Gay-Lussac’s Law (direct relationship): Charles Law (direct relationship):

II. Combined Gas Laws We can combine Boyle’s Law, Charles Law, and Gay-Lussac’s Law into one equation. The combined Gas Law equation is:

What is the Ideal Gas Law?

I. Ideal Gas Law Based on the relationships studied by Boyle, Charles, and Gay – Lussac An ideal gas is an imaginary gas whose particles are infinitely small and do not interact with each other.

II. The Kinetic Molecular Theory The Kinetic Molecular Theory is a way to explain the properties of ideal gases by examining the movement of gas particles at the microscopic level. Just like there are no “ideal” people, there are actually no ideal gases. But gases do approach ideal behavior.

II. The Kinetic Molecular Theory 1. Gases consist of tiny particles (molecules or atoms) traveling in straight lines. 2. The particles are TINY compared to the space between them. So, we do not count the volume of the particles. 3. Particles do not attract or repel, and particles do not lose energy when they collide. Space between = BIG Itty-bity Itty-bitty

Let’s use the KMT to explain some gas properties. Pressure & Temperature Diffusion Pressure & Volume Pressure & # of molecules We are about to do a demonstration and watch some videos. Take notes and draw pictures in the boxes on your worksheet. Think about how to explain what you see using the KMT (think about the constant and random motion of particles).

III. The Ideal Gas Law PV=nRT The Ideal Gas Law is: P=pressure V=volume in L n=moles R=Gas constant (0.0821 (L atm)/(K mol)) T=temperature in Kelvin.

Class Example If I have 4 moles of a gas at a pressure of 5.6 atm and a volume of 12 L, what is the temperature of this gas?

Table Talk If I have an unknown quantity of gas at a pressure of 1.2 atm, a volume of 31 L, and a temperature of 87 oC, how many moles of gas do I have?

Stop and Jot If I contain 3 moles of gas in a container with a volume of 60 L and a temperature of 400 K, what is the pressure inside this container?

Snake Game AP chemistry and ACS Olympiad require us to be able to do Ideal Gas Law Problems with relative quickness, therefore we are going to be doing the snake game to determine the answer to ideal gas law problems. You will be answering the problems alone Many of the problems will require you to spot the error in the answer

Question 1 If I have 4 moles of a gas at a pressure of 5.6 atm and a volume of 12 liters, what is the temperature? Remember R=0.0821 (Lxatm)/(Kxmol)

Question 2 If I have an unknown quantity of gas at a pressure of 1.2 atm, a volume of 31 liters, and a temperature of 360 K, how many moles of gas do I have?

Question 3 If I contain 3 moles of gas in a container with a volume of 60 liters and at a temperature of 400 K, what is the pressure inside the container?

Question 4 Spot the error in this answer: Problem – If I have 0.275 moles of gas at a temperature of -200 oC and a pressure of 1.75 atmospheres, what is the volume of the gas? Answer –

Question 5 Spot the error in this answer: If four moles of a gas at a pressure of 5.4 atmospheres have a volume of 120 liters, what is the temperature?

Question 6 Spot the error in this answer: If I have 72,000 mL of gas held at a pressure of 3.4 atm and a temperature of 225 K, how many moles of gas do I have?

Question 7 A weather ballon is filled with 150 L of helium at 23 oC and 1.00 atm. What volume does the balloon have when it has risen to a point in the atmosphere where the pressure is 0.289 atm and the temperature is -31 oC?

Question 8 If I initially have a gas at a pressure of 12 atm, a volume of 23 liters, and a temperature of 200 K, and then I raise the pressure to 14 atm and increase the temperature to 300 K, what is the new volume of the gas?

Question 9 A gas takes up a volume of 17 liters, has a pressure of 2.3 atm, and a temperature of 299 K. If I raise the temperature to 350 K and lower the pressure to 1.5 atm, what is the new volume of the gas?

Question 10 A gas at 5 L and STP is increased to 5 atm and 500 K, what is the new pressure?

Question 11 If I have 17 liters of gas at a temperature of 67 0C and a pressure of 88.89 atm, what will be the volume of the gas if I bring the gas to STP?

Question 12 You have a 15 moles of a gas at STP. What volume does this gas occupy?

Rate Yourself On LTs 6.1 – 6.10 rate yourself 1 – 4 based on your measured level of mastery.

Closing Time Lab Report Due Next Week!