# Ch. 5: Gases and the Gas Laws

## 16 terms

### atmosphere

~the major components of the earth's atmosphere are nitrogen and oxygen
~pollutants added to it by factories/cars have damaging effects through the form of acid rain
~the steady increase in CO2 is causing a greenhouse effect, making temperatures rise
~55 miles above sea level, the composition of the atmosphere is the same at ground level

### atmospheric pressure/standard pressure

~higher altitudes=less weight of atmosphere=less pressure
~the air pressure at sea level can support a column of mercury 760 mm in height
~this is the weight of a KG mass on every sq. cm of surface exposed to it

### Boyle's Law

~P1V1=P2V2
~temperature is held constant

### Charles' Law

~V1/T1=V2/T2
~pressure is held constant

~P1V1/T1=P2V2/T2

### Correction of Pressure

~When the level inside is higher than the level outside => less pressure on inside --> subtract the pressure from the barometric pressure
~When the level inside is lower than the level outside => add the pressure to the barometric pressure
~if the substance is water then divide the difference between the inside and the outside by 13.6 mmHg

### Dalton's Law of Partial pressures

~P total= P1 + P2 + P3....
~multiply the percentage by the atmospheric pressure

### Gay Lussac's Law

~P1/T1=P2/T2
~volume is kept constant

### Graham's Law of Diffusion

Rate A(sqrt[MM of A])=Rate B(sqrt[MM of B])

### Hydrogen

~whenever it burns (H2 + 02) it forms water
~Electrolysis - passing an electric current through water causes it to decompose
~use activity series to replace hydrogen
-very active metal + H20= H2 + metal OH
-K, Ca, Na, Mg, Al, Zn, Pb, Tin, H, Cu, Hg, Ag, Au (decreasing down)
~with metals that react slower, use dilute acid reaction
-active metal + dilute acid = H2 + salt of acid
~physical properties:
-colorless, odorless, tasteless gas
-0.9 g/L at 1 atm, and is 1/14 as dense as air
-slightly soluble in water
-diffuses more rapidly than any other gas
~chemical properties:
-burns in air/oxygen and gives off large amt of heat
-does not support ordinary combustion
-good reducing agent

### Ideal Gas Law

~PV=nRT (n = m/MM)
~R=.0821 [Latm]/[molK]
~molecules aren't taking up space in the gas volume and no IM forces were pulling molecules closer together
~gas behaves like ideal gas @ low pressures, high temperatures: molecules are as far away from each other as possible --> condensation
~@high pressures: molecules are forced together and volume decreases -> PV is lower than that expected in the ideal gas situatin

### Kinetic Molecular Theory

~matter in all its forms is composed of extremely small particles
-space occupied by particles is ignored in comparison with the volume of the space in which they're contained
~particles of matter are in constant motion
-solids: restricted to a small space
-liquids: more random pattern
-gas: continuous, random, straight line motion
~there is no loss of energy when the particles collide with each other or with the walls of the container

### oxygen

~about 50% of earth's crust is oxygen
~it makes up 21% of the air
~mercuric oxide decomposes into oxygen: 2HgO--> 2Hg + O2
~decomposing KCLO3 (2 KClO3 + Mn02 --> 2KCl + 3O2 + MnO2)
~Mn02 lowers the temperature needed to decompose the KCl03 and speeds up the reaction
~will support combustion but won't burn
~test for oxygen: lower a glowing splint into the gas and see if oxidation increases in its rate to reignite the splint

### ozone

~this is an allotropic form of oxygen
~occurs in small quantities in the upper layers of Earth's atmosphere and can be formed in the lower atmosphere
~302 + electricity --> 203
~higher energy content = more chemically reactive than O2

### pascal

~SI unit of pressure
~101325 pascals in 760 mmHg

### torr

~760 torr=760 mmHg