M5

• STOICHIOMETRY


  The study of the quantitative relationships or ratios between two or more substances undergoing a physical change or chemical change (chemical reaction).
• STOICHIOMETRY


  This word is derived from the Greek words: stoicheion meaning "element" and metron meaning "to measure".
• MOLE


  A ____ is an SI unit for chemical quantity, denoted by the symbol "mol".
• MOLE


  This is the number of particles in exactly 12g of carbon-12.
• MOLE


  One ____ is equivalent to 6.02 x 10²³ particles of a certain substance that can be molecules, atoms, ions, formula units, or electrons.
• ONE MOLE


  Simply put, ___ ____ indicates how many representative particles are there in a certain substance, regardless if it is an element or a compound.
• The number 6.02 x 1023 is a constant, called the Avogadro's number, named after the Italian scientist Amadeo Avogadro (1776—1856). Although he wasn’t the one who actually calculated the number, he was credited with suggesting the probability of counting atoms.
• Avogadro's number is only a representative number of all the particles in a substance.
• An equal number of moles would also mean an equal number of particles and vice versa. You can calculate how many actual particles are present in a given amount of moles by using Number of particles = (mole) (Avogrado’s number) p = n AN.
• The molar mass is equal to the average atomic mass of the element in grams. For example, the average atomic mass of magnesium is 24.3 amu. This means that the molar mass of magnesium is 24.3 g.
• The molar mass of a compound is called the molecular mass or the formula mass. It is equal to the sum of all the average atomic masses of all the atoms present in a compound.
• Percent composition by mass refers to the relative amounts of each element in a compound. The number of percent composition of a compound is equal to the number of elements present in a compound.
• Percent, fractions, and ratios are an integral part of chemistry.
• Percentage compositions often involve fractions and percent; ratios are used in stoichiometry, which refers to the relationship between the amounts of substances in a compound.
• The empirical formula of a compound gives the lowest whole-number ratio of the atoms of the elements in the compound. For example, the chemical formula CH2 is an empirical formula. The ratio of the C atoms to H atoms is 1:2.
• The empirical formula of any compound provides information about the types and the relative number of atoms in the molecule or formula unit of the compound.