Calculations+involving+the+Mole+and+the+Volume+of+a+gas+and+the+Number+of+Particles

=​☆ __Calculations involving the Mole and the Volume of a gas and the Number of Particles__=

- Calulations relationg the number of moles and the volume of a gas.

 * Avogadro's Hypothesis : Equal volumes of different gases, at the same temperature and pressure, contain the same number of particles.**

Molar Volume** : The volume occupied by one mole of the gas.
 * Definition

※ __S__TANDARD EMPERATURE AND __P__RESSURE (STP) : 0℃ and 101.3kPa.

→ //Equal numbers of moles of ever gas at STP occupy identical volumes.//

● **__1 mol__ of //ANY GAS// at __STP__ has a volume of __22.4 L__. → The __MOLAR VOLUME__ of //any gas// at __STP__ is __22.4 L__.**

∴ __ 1 mol __ 　 or 　 __ 22.4 L __ 　 → 　 These conversion factors ONLY apply to **gases** and only at **STP**. 22.4 L 　　　 1 mol


 * Example**

a) What is the volume occupied by 4.25 mol of HCl(g) at STP ?

→ 　# of litres = 　4.25 mol　 ×　__22.4 L__　 = 　95.2 L Hcl →　　　　　　　　　　　　　　　1 mol

b) How many moles of Hydrogen gas are contained in a volume of 85.9 L at STP ?

→ 　# of moles = 　85.9 L　×　 __1 mol__　 =　 3.83 mol H₂ →　　　　　　　　　　　　　　 22.4 L

- Calulations relationg the number of moles and the number of particles.

 * The mole : Amount of Substance (Number of particles of the substance)
 * 1 mol 　 = 　  6.02 × 10 23 ||

6.02 × 10 23 is **AVOGADRO'S NUMBER**. It does **NOT** attach **UNITs**.
__ 1 mol particles __　 　　　　 or　　　　 　　 __ 6.02 × 10 23 particles __ 6.02 X 10 23 particles 　　　　　　　　　　　 1 mol particles

__※ mass of 1 mol in grams = (6.02 × 10 23 ) × (individual mass of atom in grams)__

→ When a particle's tomic symbol is found on the periodic table, just use the mass of the particle given in the periodic table and simply attach the unit "g" to get the molar mass.


 * ※ "Particles" refer to "atoms", "molecules" or "ions" depending on the context.

Example**

a) How many molecules are there in 0.125 mol of molecules ?

→　# of molecules　=　0.125 mol 　×　 __6.02 × 10 23 molecules__ 　=　7.53 × 10 22 molecules →　　　　　　　　　　　　　　　　　　　　　　1 mol

b) How many moles of N atoms are there in 5.00 × 10 13 N atoms ?

→　# of moles 　= 　5.00 × 10 13 　atoms　×　　　　__1 mol__　　　　　=　8.31 × 10 -11 mol →　　　　　　　　　　　　　　　　　　　　　　6.02 × 10 23 atoms

c) A particular variety of carbon atom has a mass of 2.16 × 10 -23 g/atom. What is the mass of a mole of this variety of carbn atom ?

→　　mass　=　__2.16 × 10 -23 g__　×　__6.02 × 10 23 atoms__　=　13.0 g/mol →　　　　　　　　　1 atom　　　　　　　　1 mol