Chapter 7 Flashcards
formula mass & alt names
the mass of a single molecule or formula unit (the non whole numbers seen on the periodic table)
“formula weight” “molecular mass” “Molecular weight”
Example: what is the formula mass of a water molecule
2(1.01u)+1(16.00u)=18.02u
Percent composition of one element =
[(mass of one element)/(mass of compound)] x100%
mass spectrometry
a technique used to measure the mass of molecules
contains three components
ionizing chamber- converts neutral molecules into ions
electric field- causes the pathways of the charged particles to curve
detector-particles strike the detector. mass of is calculated by the size of the electric field, the charge on the particle and and the precise point at which the particle hits the detector
elemental analysis
a technique used to measure percent composition, uses combustion reactions to form simpler products.
1 mole (mol) =
6.02x10^23 units of anything (like the term a dozen)
Avogadro’s number
6.o2x10^23
Molar mass
when something is measured in grams/(per)mole
Converting between grams and moles
Use molar mass as the conversion factor
converting between moles and particles
Using Avogadro’s number
6.02x10^23 particles=1 mole
relating atoms to grams
atoms–>(using molar mass) converted to moles—> then converted to atoms (using Avogadro’s number)
molesA to moles B
conversion factor using a mole ratio from the balanced equation
Stoichiometry
using the amount of one material to predict the amount of another, based on the balanced equation.
gram-to-gram problem
grams A–>moles A—->moles B—>grams B
the limiting reagent
the reactant that runs out first and limits the amount of product that can be produced
the reagent which can produce the least amount of product is the limiting reagent
