Unit 3 Flashcards
mole
- a mole is a unit for a specific number of things (particles, atoms, photons, etc.)
- relates mass of a substance to the number of particles it contains; is a convenient unit for expressing macroscopic quantities (atoms or molecules) involved in chemical reactions
Avogadro’s #
6.022x10^23
equivalent to one mole
Molar Mass (MM)
the mass (in grams) of one mole of the substance (atom/molecule/formula unit)
Molecular Mass
The mass (in grams) equal to the mass of an individual atom or molecule (in amu)
Law of Conservation of Mass
the sum of the mass of the reactants in a chemical equation must equal the sum of the masses of the products
Also, total charge of reactant side and product side must be equal
Chemical equation
Describe ratios of reactants (the substances that are consumed) and products (the substances that are formed) during a chemical reaction
coefficients
indicates ratios of reactants and products on molecular or molar level
Stoichiometry
the relationship between the relative quantities of substances taking part in a reaction or forming a compound, typically a ratio of whole integers
Percent composition
the mass percentage of each element in a compound
Mass spectrometers
instruments to determine the mass of substances by
* converting molecules into ions
* separate ions based on mass/charge ratio
molecular formula
actual molar ratio of elements in a coumpound, equal to some multiple of the empirical formula
What is needed to determine molecular formula?
- Empirical formula
- molecular mass
combustion reactions
reactions between oxygen (O2) and another element in a compound
hydrocarbons
molecular compounds composed of only hydrogen and carbon
How is the limiting reactant identified?
- # of moles of reactants
- stochiometry of balanced chemical equation
