Química 3

Gases

Fully described by

Can be compared only at STP (Standard Temperature Pressure)

Explained by the ..... >> Kinetic-molecular theory << ...... which describes an ..... >> Ideal Gas << ...... which is ......>> Imaginary <<

PV=nRT

Volume

Temperature

Pressure

Number of molecules

The ideal gas has no attraction nor repulsion forces, their collisions are perfectly elastic.

V volume

n mols

P pressure

R gas constant

T temperature (kelvin)

0.082 atm.L/mol.K

At STP 1 mol of gas = 22.4L

Formulas

Boyle (at constant n and T)

Charles (at constant n and P)

Gay Lussac (at constant n and V)

Avogrado (at constant P and T)

V is inversly proportionate to P

P1V1=P2V2

V is proportionate to T

V1 / T1 = V2 / T2

P is proportionate to T

P1 / T1 = P2 / T2

V is proportionate to n

V1 / n1 = V2 / n2

Chemical Reaction

It's a process where the initial substances under go chemical changes producing new substances at the end.

Exothermic (releases heat)

Endothermic (absorbs heat)

Steps to Write Reactions

  1. Analyze the products and reactants using stoichiometry
  1. Balance the equation
  1. Identify the type of reaction

Diatomic Molecules

H2, N2, O2, F2, Cl2, Br2, I2

Types of reactions

Decomposition

Single displacement

Synthesis

Double displacement

Special reactions

Neutralization

Combustion

acid + base = water + salt

hydrocarbon + oxygen = carbon dioxide + water

stoichiometry

Limitant reactant

You balance the equation, then the problem tells you how many grams of each substance were you given. You make the relation of how many mols you actually have. You make the relation about which one is going to delimit the quantity of mols of the resulting substance that you are going to make, by the limiting reactant you will obtain the amount of substance you could make.