Quiz A toy balloon has an internal pressure of 1.05 atm and a volume of 5.0 L. If the temperature where the balloon is released is 20.0 0C, what will happen to the volume when the balloon rises to an altitude where the pressure is 0.65 atm and the temperature is –15 0C? What is the volume of 0.4 moles of O2 at STP? A sample of gas is collected over water at a temperature of 35.0oC when the barometric pressure reading is 742.0 mm Hg. What is the partial pressure of the dry gas? (@35oC, PH2O = 42.2 mm Hg) If I have 12 moles of iodine gas (I2), what will the volume be if temperature is 310K and the pressure is 0.8 atm?

A gas at 273K at 800. torr is heated to 390K A gas at 273K at 800. torr is heated to 390K. What is the new pressure of the gas? A gas occupies 11.4 L at 25°C. What is the temperature in °C of the gas if the volume decreases to 5.6L? 2045 kPa is how many psi? A gas occupies 11.4 L at a pressure of 36 mm Hg. What is the volume when the pressure is increased to 50 mm Hg? State the Gay Lussacs’ law in words.

A gas at 273K at 800. torr is heated to 390K A gas at 273K at 800. torr is heated to 390K. What is the new pressure of the gas? A gas occupies 11.4 L at 25°C. What is the temperature in °C of the gas if the volume decreases to 5.6L? 2045 kPa is how many psi? A gas occupies 11.4 L at a pressure of 36 mm Hg. What is the volume when the pressure is increased to 50 mm Hg? State the Charles’ law in words.

1142 torr -127 °C 296.8 psi 8.2 L GL law states Pressure and temperature are directly related

Lecture 6.2 Ideal Gas Law

We will use a simplified version, called the ideal gas law Real gasses have many different forces acting on it making it very difficult to calculate variables accurately. Particles itself has small volume Particles have small attraction between each other NASA would have to use complex equations to account for the minute volume of particles and attraction We will use a simplified version, called the ideal gas law

Ideal gas law (basically the combined gas law, but it also accounts for # of moles) PV=nRT P=pressure in atm V=volume in L n= # of moles R= a constant, equal to .0821 𝑎𝑡𝑚·𝐿 𝑚𝑜𝑙·𝐾 T= temperature in Kelvin

P= V= n= T=

Using the ideal gas law, we can find P, V, n, or T. If I have 3 moles of oxygen gas at 320 K in a 6L bottle, what is the pressure? P= V= n= R= T=

If I have a gas that is inside a 2. 5 L ballon, with a pressure of 2 If I have a gas that is inside a 2.5 L ballon, with a pressure of 2.75 atm, at a temperature 297 K, how many moles of the gas will be in the balloon? P= V= n= R= T= =0.28 mol

Molar Volume If I have a mole of any gas at 1 atm and 273K (0°C), it will always have a volume of 22.4 L 22.4 L or 1 mole 1 mole 22.4 L 1 atm and 273K condition is called the Standard Temperature and Pressure (STP) Try solving using ideal gas law V= nRT/P 1*R*273/1= 22.4

If I have 2 moles of oxygen gas (O2) at STP, what is the volume of the gas? If I have 2 moles of helium gas (He)at STP, what is the volume of the gas? If I have 4.32 moles of N2 at STP, what is the volume of the gas?

If I have 44.8 L of O2 at STP, what is the number of moles of the gas? If I have 30.6 L of fluorine gas (F2) at STP, what is the number of moles of the gas?

Density of Gasses D=M/V The density of a gas at STP is= D= molar mass molar volume

What is the density of He at STP? The molar mass of He is 4.00g/mol Molar volume of any gas at STP is 22.4 L 4.00g/mol = 0.179 g/L 22.4L/mol

Practice What is the density of chlorine gas (Cl2) at STP? What is the density of argon gas (Ar) at STP?

What is the molar mass of a gas that has a density of 1.836 g/L at STP? 1.836 g/L = X g/mol 22.4 L/mol X= 41.13 g/mol

Practice What is the molar mass of a gas that has a density of 4.6 g/L at STP? What is the molar mass of a gas that has a density of 0.434 g/L at STP?

Partial Pressure The total pressure of a mixture of gases equal to the sum of the partial pressure Ptotal = P1 + P2 + . . . Pn

If carbon dioxide, nitrogen, and oxygen are in a container and exert a pressure of 760 torr, and the partial pressure of carbon dixoide is 0.285 torr, the partial pressure of nitrogen is 593.525 torr, what is the partial pressure of oxygen? PTotal = PCO2 + PN2 + PO2 760= 0.285 + 593.525 + X PO2 = 166 Torr

The atmosphere’s composition is 78% nitrogen, 21% oxygen, 1% argon The atmosphere’s composition is 78% nitrogen, 21% oxygen, 1% argon. If the atmospheric pressure was 760 mm Hg, what pressure would be N? O? Ar? 760 * .78 = 590 mmHg N2 760 * .21 = 160 mmHg O2 760 * .01 = 8 mmHg Ar

Quiz 7.4 If I have 5 moles of N2 at STP, what is the volume? If I have 35 L of O2 at STP, how many moles is it? If I have a gas that is inside a 5.5 L balloon, with a pressure of 2 atm, at a temperature of 50⁰C, how many moles of the gas will be in the balloon?