1. GASES

2. Identify naturally occurring atmospheric gases. Examine the historical development of pressure. Include: Torricelli, Pascal Describe the various units of pressure. Include: atmospheres (atm), kilopascals (kPa), millimetres of mercury (mmHg) Additional KEY Terms barometer

3. Earth’s air is composed of two types of gases: PermanentVariable Nitrogen 78.1%Water vapor 0 - 4% Oxygen 20.9%Carbon Dioxide 0.035% Argon 0.9%Methane 0.0002% Neon 0.002%Ozone 0.000004% Helium 0.0005% Krypton 0.0001% Hydrogen 0.00005%

4. Torricelli (1608-1647) developed the first Barometer - measures air pressure Height of mercury supported by atmospheric pressure at sea level is 760 mm.

5. Pascal (1623-1662) added to Torricelli’s “barometer.” Height affects the pressure of the atmosphere. Gay-Lussac (1778-1850) observed the law of combining volumes in chemical reactions. 2 H 2 + O 2  2 H 2 O Two volumes of hydrogen combined with one volume of oxygen to form two volumes of water.

6. Manometer – measures gas pressure:

7. Gas/Vapour Pressure: P gas = P atm + h (greater than air) P gas = P atm – h (less than air)

8. UNITS

9. Dimensional Analysis Problem-solving method using relationships to change units without changing value. Relationships are made by relating two things by their equivalent "amounts" as a ratio. 1 filling OR 2 cookies 2 cookies1 filling

10. Dimensional Analysis (Converting Units) : 1.Determine the unit ratio needed. 2. Multiply the base unit by the unit ratio. (make sure you have the new unit on top) 1.20 fillings = ? cookies 20 fillings x 2 cookies = 40 cookies 1 fillings 1 fillings OR2 cookies 2 cookies 1 filling

11. Prefix SymbolFactor of base unitFraction of base unit gigaG1 000 000 0001 billion megaM1 000 0001 million kilo k1 0001 thousand hecto h1001 hundred deca da101 ten 1 decid0.11/10 th centic0.011/100 th millim0.0011/1000 th microμ0.000 0011/1 000 000 th nanon0.000 000 0011/1000 000 000 th

12. 2. 3 m = ? cm 1 m or 100 cm 100 cm 1 m 3 m x 100 cm = 300 cm 1 m

13. 3. 5 kL = ? mL 1 kL and 1 L 1000 L 1000 mL 5 kL x 1000 L x 1000 mL = 5 000 000 mL 1 kL 1 L *need to multiply by TWO factors: kL  L  mL

14. 1. atmosphere (atm): 1 atm = 760 mmHg = 101.325 kPa 2. Pascal (Pa) – standard international (SI) units. Defined as 1 Newton of force per m 2. Use kiloPascals. 3. Millimetres of mercury (mmHg) – not common. 4. Pounds per square inch (psi) - Imperial 1 kPa is equal to 0.145 psi 1 atm is equal to 14.7 psi.

15. P gas = 762 mm + 15 mm = 777 mmHg What is the pressure of the gas in kPa? 777 mmHg x 101.3 kPa = 103.6 kPa 760 mmHg

16. Gas pressure is due to the force of gaseous particles colliding with their container. Torricelli invented the barometer to measure atmospheric pressure. Units used: mmHg, atm, kPa, psi Using a manometer: gas pressure > air pressure P gas = P atm + h gas pressure < air pressure P gas = P atm – h.

17. CAN YOU / HAVE YOU? Identify naturally occurring atmospheric gases. Examine the historical development of pressure. Include: Torricelli, Pascal Describe the various units of pressure. Include: atmospheres (atm), kilopascals (kPa), millimetres of mercury (mmHg) Additional KEY Terms barometer