Ch.5 - GasesSee all chapters
All Chapters
Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds
Understanding Pressure

Concept #1: Pressure vs. Force 

Concept #2: The different units for Pressure

Although the SI unit for pressure is the Pascal, most professors use atm, mmHg or torrs as the everyday units for pressure. 

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Example #1: A geochemist heats a limestone (CaCO3) sample and collects the CO2 released in an evacuated flask. The CO2 pressure is 283.7 mmHg. Calculate the CO2 pressure in torrs and atmospheres.

The conversion of units of pressure is simply a dimensional analysis question. Recall the dimensional analysis relationships been volume and length.  

Practice: If the barometer in a laboratory reads 34.2 inHg what is the pressure in bars? (1 in = 2.54 cm)

Additional Problems
Which of the following indicates the greatest pressure? a. 1 atm b. 777 torr c. 5.5 mm Hg d. 1000 Pa e. 12 psi
The pressure in Denver. Colorado (elevation 5280 ft). averages about 24.9 in mmHg. Convert this pressure to a. atm
The pressure on top of Mt. Everest averages about 235 mmHg. Convert this pressure to a. torr
The world record for lowest pressure (at sea level) was 652.5 mmHg recorded inside Typhoon Tip on October 12,1979, in the Western Pacifie Ocean. Convert this pressure to  a. torr
The pressure in Denver. Colorado (elevation 5280 ft). averages about 24.9 in Hg. Convert this pressure to b. mmHg
The pressure in Denver. Colorado (elevation 5280 ft). averages about 24.9 in Hg. Convert this pressure to c. psi
Which of the following is  NOT a unit for pressure? A) Pa         B) mmHg        C) atm             D) torr             E) liter
The pressure in Denver. Colorado (elevation 5280 ft). averages about 24.9 in Hg. Convert this pressure to d. Pa
The pressure on top of Mt. Everest averages about 235 mmHg. Convert this pressure to b. psi
The pressure on top of Mt. Everest averages about 235 mmHg. Convert this pressure to c. in Hg
The pressure on top of Mt. Everest averages about 235 mmHg. Convert this pressure to d. atm
The world record for lowest pressure (at sea level) was 652.5 mmHg recorded inside Typhoon Tip on October 12,1979, in the Western Pacifie Ocean. Convert this pressure to  b. atm
The world record for lowest pressure (at sea level) was 652.5 mmHg recorded inside Typhoon Tip on October 12,1979, in the Western Pacifie Ocean. Convert this pressure to  c. in Hg
The world record for lowest pressure (at sea level) was 652.5 mmHg recorded inside Typhoon Tip on October 12,1979, in the Western Pacifie Ocean. Convert this pressure to  d. psi
Convert 1.50 atm to torr. A) 760 torr B) 875 torr C) 1140 torr D) 1000 torr E) 1520 torr
The pressure on top of Mt. Everest averages about 235 mmHg.1.) Convert this pressure to torr.2.) Convert this pressure to psi.3.) Convert this pressure to inHg.4.) Convert this pressure to atm.
Convert 1.50 atm to torr. A) 760 torr B) 875 torr C) 1140 torr D) 1000 torr E) 1520 torr
The atmospheric pressure is 700 mm Hg. What is the pressure in inches of Hg?A) 16.0 in HgB) 0.921 in HgC) 13.5 in HgD) 27.6 in HgE) 32.5 in Hg
The air pressure in a volleyball is 75 psi. What is this pressure in torr ( 1 psi = 14.7 atm, 1 atm = 101,325 Pa = 760 torr)?a. 75,000 torrb. 393,300 torrc. 76,500 torrd. 837,900 torre. 562 torr
A sample of N2O gas has a density of 2.85 g/L at 298 K. What is the pressure of the gas (in mmHg)? 
An oxygen tank contains oxygen (O2) at a pressure of 9 50 atm. Part AWhat is the pressure in the tank in torr? Part BWhat is the pressure in the tank in mmHg?
The pressure 70.0 meters under water is 788 kPa.What is this pressure in atm?What is this pressure in mmHg? 
High-pressure liquid chromatography (HPLC) is a method used in chemistry and biochemistry to purify chemical substances. The pressures used in this procedure range from around 500 kilopascals (500,000 Pa) to about 60,000 kPa (60,000,000 Pa). It is often convenient to know the pressure in torr. If an HPLC procedure is running at a pressure of 2.90 x 108 Pa, what is its running pressure in torr? Express the pressure numerically in torr.
The atmospheric pressure in New York City on a certain day was 768 mm Hg. What was the pressure in kPa?a. 1.02 x 105 kPa b. 584 kPa c. 5.76 x 10-3 kPa d. 102 kPa e. none of the above
The pressure in car tires is often measured in pounds per square inch (lb/in.2), with the recommended pressure being in the range of 25 to 45 lb/in.2. Suppose a tire has a pressure of 37.5 lb/in.2. Convert 37.5 lb/in.2 to its equivalent in atmospheres. Express the pressure numerically in atmospheres.
On a climb up Mt. Whitney, the atmospheric pressure is 531 mmHg.Part A  What is the pressure in atm? Part B What is the pressure in torr? 
An airplane cabin is pressurized to 620 mmHg. What is the pressure inside the cabin in atmospheres?
The atmospheric pressure on the surface of Venus is 9120. kPa. Calculate the atmospheric pressure in atm. Be sure your answer has the right number of significant digits.
The density of mercury is 13.5 g/mL and the density of water is 1.00 g/mL. lf a mercury barometer reads 727 mmHg, what is the barometric pressure in cm H 2O?
An ordinary gasoline can measuring 30.0 cm by 15.0 cm by 10.0 cm is evacuated with a vacuum pump. Assuming that virtually all of the air can be removed from inside the can, and that atmospheric pressure is 14.7 psi, what is the total force (in pounds) on the surface of the can?