Stoichiometry is the basis of chemical calculations

Here are the materials you need to know to understand, from the concept of moles and molar masses, empirical formulas and molecular formulas, basic stoichiometry of solutions and ideal gases, and the writing and equalization of reactions, with examples of problems and discussions.

 The Concept of Moles and Molar Mass

In SI systems, one mole is defined as the sum of the material composed of entities (atoms, molecules, or other particles) a sum of the atoms in 12 grams of carbon-12. The value of the number of atoms is 6.022 × 1023 called the Avogadro number, NA.

 Empirical Formulas and Molecular Formulas

 

Glucose has a molecular formula C6H12O6 which is a folding of 6 times its empirical formula, CH2O.

Molecular formula ≡ (empirical formula) n

 

Basic Stoichiometric Solution

 

Molarity (M) is defined as the number of moles of solute per liter of solution.

 

 Basic Ideal Gas Stoichiometry

 

The molar volume, Vm, is defined as the volume of 1 mol entity (atom, ion, molecule, unit of formula) of matter. The unit of the molar volume (Vm) is L / mol.

V_m = \ frac {V} {n}

Avogadro's law states that at certain pressures and temperatures and fixed, the volume of the gas is directly proportional to the amount of gas.

In the STP state (P = 1 atm, T = 273 K), ideal gas Vm = 22.414 L / mol In the case of RTP / ATP (P = 1 atm, T = 298 K), Vm ideal gas = 24 L / mol

 

Stoichiometry Reaction

In chemical reactions, the amount of reacting reactants is sometimes incompatible with the stoichiometric amount of the reaction (not in accordance with the coefficient ratio of the equivalent equation). Therefore, there will be reactants that have reacted first compared to other reactants. The reactants that remain after reacting are called excess reagents. The out-of-date reactant is called a limiting reagent. After the barrier reagents are exhausted, no more reaction products are formed. Thus, the number of limiting reagents determines the amount of product produced.