Chapter 3: The Mole Concept & Stoichiometry Flashcards
differentiate the terms: atomic mass, relative atomic mass, molecular mass, molar mass
atomic mass: mass of a single atom
relative atomic mass: avg mass of naturally occurring mixture of isotopes
molecular mass: mass of a single molecule
molar mass (g/mol): mass of 1 mole of particles (**molar mass is numerically equivalent to atomic mass of an element)
recall: molecule held together by covalent bonds ie. H2O
explain difference between molecular formula & empirical formula
molecular formula indicates type & number of atoms in a molecule ie. H2O, C6H12O6
empirical formula is the ‘simplest formula’ form, indicating mole ratio of elements present in a compound ie. molecular formula of glucose is C6H12O6 but empirical formula becomes CH2O
define mole based on Avogadro’s constant
the mole is defined as the amount of a substance that contains as many elementary entities as there are atoms in exactly 12g of carbon-12
mole concept deals with large number of atoms, molecules or ions to arrive at a measurable term for subatomic particles, the experimentally determined number is avogadros number (NA)
1 mole of any substance contains 6.022 x 10^-23 particles (atoms/molecules/ions)
state formula for percent composition by mass
% mass of an element = (n*atomic mass of element divided by molecular mass of compound) *100
explain irreversible chemical reaction
An irreversible reaction is a reaction that proceeds to completion.
explain combination (synthesis), decomposition, and combustion chemical reactions
combination occurs when two or more reactants combine to form a single product
decomposition occurs when two or more products form from a single reactant.
Combustion is a chemical change when a substance containing C and H and/or O in oxygen to produce CO2 & H2O.
explain balanced chemical equations
a balanced chemical equation is based on the Law of Conservation of Mass -> Mass is neither created nor destroyed in ordinary chemical changes
The number/mole of atoms of each element must be the same on both sides of equation.
By convention, reactants are found on the left hand side while products are found on the right hand side of the chemical equation.
explain stoichiometry
it shows the quantitative relationship of reactants & products using a balanced chemical equation (assumption: reaction must be completed)
stoichiometric coefficients establish the MOLE RATIO between reactants and products
