chem end of freshmen year final Flashcards
(49 cards)
dozen
12
ream of paper
500 sheets
why is it useful to use units like dozen or ream
it determines how many items make up a particular unit.
gross of pencils
144 pencils
mole
SI unit of measurement for chemicals, a specific quantity that doesnt change. ( for atoms, molecules, ions or furmula units)
unit of mol:
mol
symbol of mol
n
Avogagdro’s number
number of things in 1 mole = 6.022 × 10²³
representative particles of elements
atoms
representative particles of covalent compounds
molecules
representative particles of ionic compounds
formula units
a mole is a collection of
6.022 × 10²³
molar mass
mass of one mole of any substance in gram
unit of molar mass
gram per mol (gl/mol)
how is molar mass of element found
by looking at the atomic mass of the element on the periodic table.
another names for molar mass
relative atomic mass (RAM), relative molecular mass (RMM), gram formula mass (gfm), formula mass, molar mass, molecular weight.
the equal of any element’s molar mass
its atomic mass
molar mass of a chemical compound
= to the sum of the molar masses of all the atoms in 1 molecule of that compound
molar mass’s relation to avogadro’s constant
molar mass = mass of 6.022 × 10²³ particles
relationship between the number of moles and the mass of a substance
number of moles x molar mass = mass of a substance
Actication energy (Ea)
the energy needed to get a reaction started
what do reactant molecules need when they collide to form products
energy equal or more than Ea
transition state
a temporary stage when all bonds in the reactants are broken and the atoms are ready to form new bonds. proucts.
∆H
enthalpy change, heat absorbed or released during a reaction
