Stoichiometry - (Chemistry)

Mass A → mol A → mol B

Mass A x 1mol A/molar mass A x mole ratio B/ A = moles B

Mass A → mol A → mol B → mass B

mass A/ molar mass A x mol A/1 x mole ratio B / A x 1/ mol B x molar mass B/ mol B = mass of B

Balance So2 + O2 → SO3

2SO2 + O2 → 2SO3

Balance CH4 + Cl2 → CCl4 + HCl

CH4 + 4Cl2 → CCl4 + 4HCl

Chemical equation

Represents reactants and products in a chemical reaction by symbols and formulas

How to know if a chemical reaction took place

• Evolution of energy as heat and light

• Color change

• Production of gas / bubbles form

• Formation of precipitation (a solid formed by a change in a solution)

Coefficient

A small whole number that appears in front of a formula in a chemical equation

Word equation

An equation where the reactants and the products in a chemical reaction are represented by words

Formula equation

Represents the reactants and products of a chemical reaction by their symbols or formulas

Reversible reaction

A chemical reaction where the products reform the original reactants

Indicated by ⇆

Synthesis reaction or composition reaction

Two or more substances combine to make a new compound

General equation for synthesis reaction or composition reaction

A + C → AX

Decomposition reaction

A compound that undergoes a reaction that makes 2 or more single substances

Indicated with a △ above the arrow, meaning it’s being heated

Electrolysis

Decomposition of a substance by an electric current

Single displacement reaction

One element replaces a similar element in a compound

Double displacement reaction

One or two compounds exchange places to form new compounds

Combustion reaction

A substance combines with oxygen, releasing a large amount of energy in the form of light and heat

Synthesis formula

A + B → AB

Decomposition formula

AB → A + B

Single displacement formula

A + BC → B + AC

Double displacement formula

AB + CD → AD + BC

Activity series

A list of elements organized according to the ease that the element undergoes in certain chemical reactions

Catalyst

A substance that increases the rate of a chemical reaction without making itself undergo any permanent chemical change

Aqueous solution

A solution where water is solvent shown in chemical equations as (aq)

Composition stoichiometry

It deals with mass relationships of elements in compounds

Reaction stoichiometry

Invoices mass relationships between reactants and products in a chemical reaction

Formula of mass and mole with given and unknown

Mass → mole → mole → mass

Given → given → unknown → unknown

When your given the amount of a substance in moles and have to calculate the amount of moles in another substance in the chemical reaction, the general plan is:

Amount of given substance (mol) → amount of unknown substance (mol) or mole → mole

When given the amount in moles of one substance and asked to calculate the mass(g) of another substance in the reaction, the general plan is:

Amount of given substance (mol) → amount of unknown substance (mol) → mass of unknown substance (g) or mole → mole → mass

When given the mass of a substance and have to calculate the amount of moles of another substance in the reaction, the general plan is:

Mass of given substance (g) → amount of given substance (mol) → amount of unknown substance (mol

or mass → mole → mole

When given the mass of one substance and asked to calculate the mass of another substance in the raction, the general plan is:

Mass of given substance (g) → amount of given substance (mol) → amount of unknown substance (mol) → mass of unknown substance or mass → mole → mole → mass

Factor used to convert mole to mole

Conversion factor

Mole ratio

A conversion factor that relates the amounts in moles of any two substances involved in a chemical reaction; the mole ratio is obtained directly from the balanced chemical equation

Limiting reactant

The reactant that limits the amount of the other reactant that can combine and the amount of product that can form in a chemical equation

Excess reactant

The substance that’s not used up completely in a reaction

Actual yield

The measured amount of a product obtained from a reaction is the actual yield of that product

Theoretical yield

The maximum amount of product that can be produced from a given amount of reactant (an actual yield cannot be greater than a theoretical yield)

Percentage yield

The ratio of the actual yield to the theoretical yield multiplied by 100

Percentage yield formula

Actual yield / theoretical yield x 100

(Theoretical is always the bigger number)