Compounds and Stoichiometry Flashcards
What are compounds?
pure substances composed of two or more elements in a fixed proportion
What is a molecule?
combination of two or more atoms held together by covalent bonds
What is a formula unit?
represents the empirical formula of the compound
Molecular weight vs formula weight
Molecular weight - sum of atomic weights of the atoms
Formula weight - sum of atomic weights of the ions
What is a mole?
a quantity of any substance and is defined by Avogadro’s number = 6.022 x 10^23. This based on the number of particles in 12 grams of carbon.
What is the relationship between moles and molecular/formula weight?
one mole of a compound is equal to the molecular/formula weight of the compound
What is molar mass?
the mass of one mole of a compound
What is the equation for moles?
moles = mass of sample (g) / molar mass (g/mol)
What is gram equivalent weight?
gram equivalent weight = molar mass / n
n = number of particles of interest produced or consumed per molecule of the compound in the reaction
What is the equation for equivalents?
equivalents = mass of compounds (g) / gram equivalent weight (g)
What is normality?
(N) measure of concentration - equivalents/L
What is the equation for molarity?
Molarity = Normality / n
What is the Law of Constant Composition?
any pure sample of a given compound will contain the same elements in an identical mass ratio
What is the empirical formula?
the simplest whole number ration of elements in a compound
What is the molecular formula?
exact number of atoms of each element in a compound
What is percent composition formula?
% composition = mass of the element in formula/molar mass x 100
What is a combination reaction?
has two or more reactants to form one product; always more reactants than products
What is a decomposition reaction?
single reactant that breaks down into two or more products
What is a combustion reaction?
special type of reaction that involves a fuel and oxidant; mostly reactants react to for carbon dioxide and water
What is a single-displacement reaction?
occurs when an atom or ion in a compound is replaced by an atom or ion of another element
What is a double-displacement reactions/metathesis reaction?
elements from two different compounds swap places with each other to form two new compounds
What are neutralization reactions?
a specific kind of double displacement reactions in which an acid reacts with a base to produce a salt and usually water
What are three rules of doing stoichiometry problems?
(1) Convert from given units to moles
(2) Use the mole ratio
(3) Convert from moles to the desired units
What is theoretical yield?
the maximum amount of product that can be generated as predicted from the balanced equation, assuming that all the limiting reactant is consumed, no side reactions have occurred and the entire product has been collected
