Chemistry U5 11

Solids

* Tightly packed particles 
* Crystal lattice 
* Definite shape and volume 
* Limited to no movement of particles 
* Affected by gravity 

Gases

* Particles move independently of one another 
* High degree of disorder (bumping into each other) 
* Vibrational, rotational and translational energy 
* Particles flow in all direction 
* Not affected by gravity 
* Expand to fill the volume of a container

Three factors affecting gases

* Pressure 
* Temperature 
* Volume

Liquids

* More loosely packed particles compared to solids 
* Take the shape of container or vessel 
* Move with vibrational and rotational energy 
* Affected by gravity

Ideal gas

follow the kinetic molecular theory

Kinetic Molecular theory

* **Gas particles have negligible volume**: mostly empty space in a container of gas 
* **They have no attraction/ repulsion to each other** 
* They have rotational, vibrational and translational movement 
* Their KE is directly proportional to temperature, higher temp = higher kinetic energy 

Pressure

 the units of measurement of the amount of force applied to a unit area of surface

* 1 atm
* 760 torr
* 101.3 kPa

Boyle’s Law:

* **Volume of a gas is inversely proportional to pressure**, during which **temperature must remain constant**
* **V1P1 = V2P2**

The Kelvin scale and absolute 0: 

* Gas particles stop moving at -273 degrees celsius, volume and KE of gas is 0 
* Tk = degreescelcius + 273.15

Charles’s Law: 

* **Volume of a fixed mass of gas is proportional to its Kelvin temperature**, during which the **pressure must be constant**
* **V1/T1=V2/T2**

Gay-Lussac’s Law: 

* **The pressure of a fixed amount of gas is directly proportional to its Kelvin temperature**, **during which the volume must be constant** 
* **P1/T1=P2/T2**

Combined gas law:

 Combines boyles, charles and gay lussacs laws b/c theyre all related 

* P1V1/T1 = P2V2/T2

Ideal gas

* Combined gas laws + moles 
* PV = nRT

1 mol of ideal gas @ STP and SATP

* 22.4 L @ STP
* 24.8 @ SATP

Universal gas constant: 

* R = 8.31 Kpa\*L/mol\*K

* Would it be a good idea to put propane gas tank in your car on a hot summer day?


* What gas law would u use; relationship b/t variables here? 

* No not a good idea, will explode in car 
* Gay lussacs law, pressure is directly proportional to temp, volume in gas tank remains constant 

* What will happen to your car tires if u park ur car outside on a cold winter day?


* What gas law would u use; relationship b/t variables here? 

* Gas contracts when cooled 
* Temperature drop = individual molecules slow down and take less space 
* The molecules exert less force on the tire walls because of extra space, leading to a drop in tire pressure 
* This concerns pressure and temperature and their direct proportionality, so gay lussac’s law would be used here too