Behavior of Gases Unit 2 Exploration 1.3 Units of Pressure There are various units of pressure that are commonly used (mmHg, kPa, atm)
1 atm = atmospheric pressure at sea level The following are all equal to each other: 1 atm = 760mmHg = 101.3kPa Learning Check
Does pressure increase or decrease as you go up a mountain? Why? Answer: Decreases. As you go up a mountain, the number of air molecules decreases, so there is less stuff pushing down on you. Amount of Gas at Standard Temperature and Pressure (STP)
- STP is 1 atm and 273.15K (0C) ***At STP, 1 mol of ANY gas has a volume of 22.4L*** AT STP!!! Molar Mass Molar mass is the mass of 1 mol in a substance. UNITS are g/mol
On the periodic table, the BOTTOM NUMBER in a periodic square. Example: Chlorine has a molar mass of 35.5 g/mol Pg. 74, PREDICT with your partner Kinetic Molecular Theory To summarize the lengthy explanation in the textbook, the 5
main points are as follows: 1- Gas particles are in constant motion. 2- Gas is mostly empty space. 3- Gas particles DO NOT attract/repel each other. 4- Gas particles collisions result in NO LOSS of kinetic energy. 5- Gas temperature is measuring the average kinetic
energy of the gas. What does Kinetic Molecular Theory mean??? For now, all it means is that we can assume gases follow the 5 points of Kinetic Molecular Theory when in reality they act slightly differently.
In other words, most of the time gases act IDEALLY which brings us to the Ideal Gas Law. Say Pivnert Congratulations! You have now memorized the ideal gas law. PV = nRT; here is what each variable means P = pressure; units can be atm, mmHg, or pKa
V = volume; units are L n = # of mols R = ideal gas constant; value and unit DEPENDS ON PRESSURES UNIT T = temperature; ALWAYS IN KELVIN (if C your answer will be wrong) Ideal Gas Constant R (on board)
Depending on your unit of pressure, the R value changes. UNITS If using atm for pressure, R = 0.08205 If using kPa for pressure, R = 8.314 If using mmHg for pressure, R = 62.36
Ideal Gas Worksheet, #1 together Crash Course https://www.youtube.com/watch?v=8SRAkXMu3d0
