Chapter 5: Gasses and the Gas Laws

Question 1

greenhouse effect

Answer 1

-steady rise in temperature bc of fossil fuel consumption

Question 2

properties of oxygen

Answer 2

• slightly soluble, slightly heavier than air
• will not burn
• less reactive than ozone (3O2) because of energy content

Question 3

electrolysis

Answer 3

• process of passing an electric current through water to cause it to decompose
• other methods of obtaining hydrogen include decomposing a compound, passing steam over really hot iron

Question 4

physical properties of hydrogen

Answer 4

• colorless, odorless, tasteles
• only 1/14 a dense as air
• slightly soluble in water
• diffuses faster than any other gas

Question 5

chemical properties of hydrogen

Answer 5

• high heat of combustion, can be burned in air
• good reducing agent (withdraws oxygen away easily)
• doesn’t support ordinary combustion

Question 6

atmospheric pressure/barometric pressure/air pressure

Answer 6

• force per unit area that is the result of the weight of a mixture of gases
• higher the altitude, the lower the pressure

Question 7

standard pressure

Answer 7

760 torr = 760 mm Hg =1 atm = 101,325 Pa

Question 8

mercury barometer

Answer 8

-mercury rises as more atmospheric pressure is exerted on the dish

Question 9

manometer

Answer 9

• when the mercury is on the same level, the atmospheric pressure equals the vessel
• when the pressure of the vessel is greater than the atmosphere, the pressure in the vessel= 760mm Hg + displacement
• when the pressure of the vessel is less than the atmosphere, the pressure of the vessel is 760 mm Hg - maximum displacement

Question 10

Kinetic Molecular Theory

Answer 10

• gas molecules exhibit perfectly elastic collisions (energy conserved)
• volume occupied by gas particles is negligible
• gas particles are not attracted to one another
• average KE determined by the temperature
• gas particles move in a straight line until they collide with each other or the sides of the container

Question 11

properties of gasses

Answer 11

-as the temperature increases, more molecules are able to overcome Ea, also a greater distribution of KE of gas paricles

Question 12

diffusion

Answer 12

-particles moving from area of high concentration to low concentration

Question 13

effusion

Answer 13

-particle movement through a tiny orifice into an evacuated chamber

Question 14

Graham’s Law of Effusion (Diffusion)

Answer 14

Rate1 / Rate2 = (M2 / M1)1/2

-the rate at which gas diffuses or effuses is inversely proportional to the square root of its molecular mass

Question 15

standard temperature and pressure

Answer 15

273 K, 1 atm (needed to use gas laws)

Question 16

Charles’s Law

Answer 16

V1/T1 = V2/T2 (directly proportional, true when pressure held constant)

Question 17

Boyle’s Law

Answer 17

P1V1 = P2V2 (temperature is held constant)

Question 18

Avogadro’s Law

Answer 18

V1/n1 = V2/n2

Question 19

Gay Lussac’s Law

Answer 19

P1/T1 = P2/T2

Question 20

Combined Gas Law

Answer 20

P1V1/T1 = P2V2/T2

Question 21

Dalton’s Law of Partial Pressure

Answer 21

Ptot = P1 + P2 + P3…

Question 22

Ideal gas Law

Answer 22

PV=nRT where R equals 0.08206 Latm/molK

Question 23

Gas Collected Over Water

Answer 23

subtract water vapor pressure at the given temperature from the atmospheric pressure to find partial pressure of gas