Stoichiometry: Measuring Elements in Reactions

• Stoichiometry is a chemistry section using reactants and/or products relationships in chemical reactions to determine measurements.
• Stoikhein means element and metron means measure in Greek, so stoichiometry literally translates to measuring elements.

Key Applications of Stoichiometry

• Production of daily essentials like soap, shampoo, tires, fertilizer, gasoline, deodorant, and food products.
• Environmental monitoring by measuring atmospheric ozone concentration
• Energy conversion from converting coal into gaseous fuels

Reaction Stoichiometry in Solutions

• Stoichiometric calculations can be performed for aqueous phase reactions as well as reactions in solid, liquid, or gas phases.
• Concentrations of the solution are used as conversion factors in calculations.

Important Terms

• Aqueous means dissolved in water; written as (aq) and water is the solvent.
• Aqueous solution: A solution with water as the solvent, such as table salt/sodium chloride or salt solution.
• Solute: The dissolved substance.
• Solution: A mixture of solute and solvent.
  • May be gas solid, liquid-liquid, liquid solid, liquid-gas, solid solid gas, Gas, gas liquid, gas solid, solid - liquid, and solid - gas
• Solvent: The liquid dissolving the solute.
• Concentration: The amount of solute dissolved per volume of solution.
• Molarity: The concentration of a substance in a solution, expressed as the number of solute moles per liter of solution, mol/L or M.
• Molality: The concentration of a substance in solution, expressed as the number of solute moles per kilogram of solution, mol/kg or m.
• Mole: The SI unit of amount of substance, specified by an elementary entity (atom, molecule, ion, electron, etc.), its magnitude set by fixing the Avogadro constant (6.022 x 10^23).

Steps for Solving Stoichiometry Problems

• Balance the equation.
• Convert units of a given substance to moles.
• Use the mole ratio to calculate product moles in the reaction.
• Convert moles of the wanted substance to desired units.

Ways to Convert Unit Substances

• Mole to mole (mol to mol)
• Mass to mole (gram to mol)
• Mole to mass (mol to gram)
• Mass to mass (gram to gram)

Processes

• Mole to mole calculation involves multiplying Mole A by the mole ratio (Mole B/Mole A).
• Mass to mole calculation: Mass A converted to Mole A, then multiplied by Mole Ratio (Mole B/Mole A) to get Mole B.
• Mole to mass calculation: Mole A converted to Mole B, then multiplied by the ratio of Molar Mass B / Mole B to get Mass B.
• Mass to mass calculation converts Mass A, to Mole A, then Mole B, then converted to Mass B.

Stoichiometry involves using relationships between reactants and products in chemical reactions to determine measurements. It's applied in producing daily essentials, environmental monitoring, and energy conversion. Stoichiometric calculations can be performed for aqueous phase reactions, using solution concentrations as conversion factors.