Quantitative chemistry

• Law of conservation of mass: no atoms are lost or made during a chemical reaction so the mass of the products = mass of the reactants
• In a balanced chemical equation:

  sum of Mr of reactants in quantities shown = sum of Mr of products in quantities shown
• Relative formula mass (Mr)
• Chemical​ ​amounts​ ​are​ ​measured​ ​in​ ​moles.
• The​ ​mass​ ​of​ ​one​ ​mole​ ​of​ ​a​ ​substance​ ​in​ ​grams​ ​is​ ​numerically​ ​equal​ ​to​ ​its relative​ ​formula​ ​mass
• Moles​ ​=​ ​Mass​ ​/​ ​Mr
• The​ ​number​ ​of​ ​atoms,​ ​molecules​ ​or​ ​ions​ ​in​ ​a​ ​mole​ ​of​ ​a​ ​given​ ​substance​ ​is​ ​the Avogadro​ ​constant:​ ​6.02​ ​x​ ​10​ 23​ ​ ​per​ ​mole.
• limiting​ ​reactant:​ ​the​ ​reactant​ ​that​ ​is​ ​used​ ​up​ ​/​ ​not​ ​in​ ​excess
• Percentage yield = (Amount of product produced/Maximum amount of product possible) x100
• Yield: amount of product obtained
• atom economy is a measure of the amount of starting materials that end up as useful products
• Atom economy= (Mr of desired product from reaction / sum of Mr of all reactants) x 100