Warm Up – WSHT #1 OUT!!! 1.When you increase the number of gas particles, does pressure increase, decrease or stay constant? 2.When you increase the volume of a gas, does pressure increase, decrease or stay constant? 3.When you increase the temperature of a gas, does increase, decrease or stay constant? Essential Questions EQ: How do we quantitatively describe the effects of changing the P, V, T, or n of a gas? HOT Q1: How do we convert between units of pressure? HOT Q2: How do we find the new pressure of a gas when volume changes? HOT Q3: What is the combined gas law?

Agenda Warm-Up Pressure conversions Gas Equations – Combined Gas Law Exit Ticket HOMEWORK: WORKSHEET #2 QUIZ TOMORROW!!!

Graph of relationship between the two variables Key concept 3 particles diagrams to represent 3 diff. locations on graph Real world example Pressure vs. Number of Particles Pressure vs. Temperature Pressure vs. Volume Graph of relationship between the two variables 3 particles diagrams to represent 3 diff. locations on graph Real world example Key concept Graph of relationship between the two variables Your “Discussion” section!

Consensus When the # of particles increases, pressure increases When temperature increases, Pressure increases When volume increases, Pressure decreases

Gas Conversions We have learned the relationship between pressure, volume, number of particles, and temperature, But how do we measure pressure exactly?!! There are several units for pressure, and we can use their equal values to convert from one to the next. These units include:

Notes: Gas Conversions Date FIVE UNITS OF PRESSURE: kPa  kilopascals – Used frequently by meteorologists torr  Torr – Named after the Italian scientist Evangelista Torricelli atm  atmospheres – Sea level is 1 atm mmHg  millimeters of Mercury – Hg is the atomic symbol for Mercury psi  pounds per square inch – This is the what is usually used to measure the air pressure in a car tire!

How do they relate? 1 atm = 760 torr = kPa = 760 mmHg = 14.7 psi WRITE THESE IN YOUR NOTES!!

Got it? Let’s use the values you just copied down to convert! Convert 12 psi to torr. Step 1 – Write out your units Step 2 – Fill in the numbers THAT’S IT!

Still scratching your head? Convert 2.2 atm to kPa. Step 1 – Write out your units Step 2 – Fill in the numbers WRITE THIS IN YOUR NOTES!!

Uno mas? Convert 844 torr to atm: Convert 10,450,217 mmHg to torr:

Partner Practice Convert 185 kPa to psi

Convert 912 mmHg to atm

Convert 20.7 psi to torr Convert 3.6 atm to kPa

Strong People?

Demo: King Kong’s Hand You do not have to write this down… Eye Level Particle Level

Consensus When the # of particles increases, pressure increases When temperature increases, Pressure increases When volume increases, Pressure decreases

Conceptual vs. Math Now that we have learned the relationship between pressure, volume, number of particles, and temperature, let’s look at the mathematical applications.

Notes: Combined Gas Law Four variables used in gas law problems: V = volume of the gas (L) T = temperature (K) – K stands for Kelvin. – K = o C+273 n = number of particles (moles) P = pressure (atmospheres)

Notes: Combined Gas Law Earlier, we found the relationship between all these variables. 1) Pressure and Temperature are POSITIVELY related (when one goes up, so does the other). 2) Pressure and the number of particles (n) are POSITIVELY related. 3) Pressure and volume are NEGATIVELY related (when one goes up, the other goes down)!!

What does this all boil down to? THE COMBINED GAS LAW!!! ALERT!!! P and V may be in any appropriate units as long as the same units are used on both sides of the equation T must ALWAYS be in Degrees KELVIN (ie celsius +273)

Process of solving a problem Step 1: Identify which variables the problem gives you. – For some problems this will be easy, but you really have to look through word problems!! Step 2: Cross out any variables you don’t need Step 3: Solve the remaining equation

Examples The pressure inside of a 5.1 L container is 3.2 atm. The container expands to a volume of 8.8 L. What is the new pressure inside the balloon? 1)P 1 = 3.2 atm V 1 = 5.1 L P 2 = ? V 2 = 8.8 L Step 1: Identify which variables the problem gives you. Step 2: Cross out any variables you don’t need Step 3: Solve the remaining equation

Examples Bria has a 3.2L balloon of hydrogen gas at 23 K. She leaves the balloon in her blazing hot car, and the temperature increases to 72 C. What is the new volume of the balloon? 1) V 1 = 3.2 L T 1 = 23 C V 2 = ? T 2 = 72 C You must convert to Kelvin!!!

Partner Practice The pressure inside a.83 L hot air balloon is 4.31 atm. If the volume increases to 1.44 L, what is the new pressure inside the balloon? P 1 = 4.31 atm V 1 =.83 L P 2 = ? V 2 = 1.44 L

Partner Practice A sample of gas occupies of volume of 5.5 L. After being compressed to a volume of 3.9 L, the new temperature of the sample of gas is 273 K. What was the initial temperature of the gas? V 1 = 5.5 L T 1 = ? V 2 = 3.9 L T 2 = 273K

Example The temperature inside my refrigerator is about 4 0 Celsius. If I place a balloon in my fridge that initially has a temperature of 22 0 C, a volume of 0.5 liters, and a pressure of 3 atm, what will be the volume of the balloon when the pressure decreases to 2 atm and the temperature decreases to 4 0 Celsius? V 1 = 0.5 L T 1 =22 0 C P 1 = 3 atm V 2 = ? T 2 = 4 0 C P 2 =2 atm

Partner Practice The pressure in a 3.0L bicycle tire is 2.08 atm at 25˚C in Fresno. You take the bicycle up to Huntington, where the temperature is 0 o C. The tire shrinks to a volume of 2.0 L. What is the final pressure in the tire? V 1 = 3.0 L T 1 =25 0 C P 1 = 2.08 atm V 2 = 2.0 L T 2 = 0 0 C P 2 =?

Example – Word Problems A sample of xenon gas in a 6.1 L container initially has a pressure of.85 atm. If the pressure of the gas increased to 1.9 atm, what is the new volume of the container? Step 1: Identify which variables the problem gives you. CIRCLE KEY FACTS. CROSS OUT EVERYTHING YOU DON’T NEED. Step 2: Cross out any variables you don’t need Step 3: Solve the remaining equation

Examples In a thermonuclear device, the pressure of.050 liters of gas within a bomb casing reaches atm. When the explosion destroys the bomb casing, the gas is released into the atmosphere where it reaches a pressure of 1.00 atm. What is the volume of the gas after the explosion.

Partner Practice A sample of gas at 288 K occupies a volume of 52.9 L. The gas is compressed to a volume of 41.9 L. What is the new temperature of the gas?

Partner Practice Synthetic diamonds can be manufactured at pressures of 60,000 atm. If we took 2.0 liters of gas at 1.0 atm and compressed it to a pressure of 60,000 atm, what would the volume be?

Exit Ticket 1) Convert 42 psi to torr. 2) A sample of gas at 42°C occupies a volume of 34 L. The gas is compressed to a volume of 28 L. What is the new temperature of the gas? HOMEWORK: WORKSHEET #2! Quiz tmrw! Tutoring after school today! Unit 1 Grades posted, Unit 1 Packet and Unit 1 Warm Ups posted

Warm Up – WSHT #2 OUT!!! 1. Convert 3.6 atm to kPa 2. A sample of gas occupies of volume of 5.5 L. After being compressed to a volume of 3.9 L, the new temperature of the sample of gas is 273 K. What was the initial temperature of the gas? Essential Questions EQ: How do we quantitatively measure the P, V,T, or n of a gas? HOT Q1: What is the Ideal Gas Law? HOT Q2: When do we use the Ideal Gas Law, and when do we use the Combined Gas Law? HOT Q3: What should I do I finish my quiz early?

Agenda Warm-Up – 10 min Gas Equations (45) Quiz! (25) HOMEWORK: WORKSHEET #3!!! I can show you the world…(of gas laws)… shining, shimmering, splendid…

Notes: Ideal Gas Law PV = nRT “piv nert” This equation is used to predict any of these variables when the others are held constant. P = pressure (atm) V = volume (L) n = number of particles (moles) T = temperature (KELVIN!) R = gas constant L atm mole K

Examples Equation: P*V = n*R*T A gas under a pressure of 2.3 atm and at a temperature of 293 K occupies a L container. How many moles of gas are in the container? 1)P = 2.3 atmV = L n = ? T = 293 K R = gas constant L atm Kmole

Examples.89 moles of a colorless gas occupy a volume of 84.1 L and a pressure of 3.6 atm. What is the temperature of the gas? P = 3.6 atm V = 84.1 L n =.89 mol T = ?

When Do I Use Which? Use “Ideal Gas Law” when solving for a variable and everything is held constant… used “Combined Gas Law” when something is changing and you are asked for “new” pressure, for example.

Example The temperature inside my refrigerator is about 4 0 Celsius. If I place a balloon in my fridge that initially has a temperature of 22 0 C and a volume of 0.5 liters, what will be the volume of the balloon when it is fully cooled by my refrigerator? Are you changing pressure, volume, temperature, or # of particles? Ideal or Combined?

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? Are you changing pressure, volume, temperature, or # of particles? Ideal or Combined?

Flash! 1.0 L of a gas at 1 atm is compressed to.473L. What is the new pressure of the gas? Are you changing pressure, volume, temperature, or # of particles? Ideal or Combined?

Flash! Synthetic diamonds can be manufactured at pressures of 60,000 atm. If we took 2.0 liters of gas at 1.0 atm and compressed it to a pressure of 60,000 atm, what would the volume be? Are you changing pressure, volume, temperature, or # of particles? Ideal or Combined?

Flash! 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? Are you changing pressure, volume, temperature, or # of particles? Ideal or Combined?

Flash! If I have an unknown quantity of gas held at a temperature of 1195 K in a container with a volume of 25 liters and a pressure of 560 atm, how many moles of gas do I have? Are you changing pressure, volume, temperature, or # of particles? Ideal or Combined?

Exit Ticket 1) 0.8 moles of an ideal gas are stored in a 5L container at 1.5atm. What is the Temperature of the gas? 2) A gas in a solid 8L container is initially at 32 C and 3.5 atm. The gas is cooled to 10 C what is the new pressure of the gas? YOU HAVE TO CONVERT TO K !

Quiz! No talking Only logistical questions will be answered If you finish early, start your homework (worksheet #3) HOMEWORK: WORKSHEET #3