Chapter 5: Stochiometry Flashcards
What is the average atomic mass
calculated from the isotopes of an element weighted by their relative abundances
What is the formula for atomic mass
(fraction of isotope n) (mass of isotope) + (fraction of isotope 2) (mass of isotope 2)`
what is the natural abundance
% of an element that is an isotope
what is mass spectrometry
technique used to measure the mass of atoms and the % abundance of isotopes
What is a mole?
counting unit
bridge from big to small
What is Avogadro’s number
6.022X10^23
What is avogadro’s number equal to
1 mole
What is molar mass
mass of 1 mole of a substance (g/mol)
How do you find molar mass
look at the periodic table
What is the molecular mass
in combination with Avogadro’s number it is used to determine the number of atoms to number of molecules
What is the empirical formula
the lowest whole number ratio of atoms
What can you use to calculate percent composition
the empirical formula
what does the % mean in % composition formula
the percentage by mass contributed by each element in the substance
how do you calculate empirical formulas
- ) mass % to grams. Assume 100 grams
- ) Grams to Moles (molar mass)
- ) Moles to empirical formula
- ) calculate the mole ratio by dividing the smallest number of moles
what is the formula obtained from % composition
the empirical formula always
what is the molecular formula
the exact number of atoms
what do the subscripts in a molecular formula represent
the whole number multiple of the corresponding subscripts in its empirical formula
what is the law of conservation of mass
whatever you start with is what you end with
what is a chemical reaction
process that leads to the chemical transformation of one set of chemical substances to another.
what are the products of the combustion reaction
CO2 and H20
What do the letters in () represent
the states
what is the symbol for gas
(g)
What is the symbol for liquid
(l)
what is the symbol for solid
(s)
What is the symbol for aqueous
(aq)
what do the subscripts tell you
the number of atoms that are present
what are coefficients
tell the number of molecules present
-used to balance the equation
What is stoichiometry
the quantitative study of the amounts of reactants
why do we use stoichiometry
avoid using large excess amounts of costly chemicals
what is the law of conservation of mass
mass cannot be created or destroyed
mass is conserved
what are the types of stoichiometry problems
mole-mole
mass-mass
what is the limting reactant
the reactant present in the smallest stoichiometric amount
- the reactant you’ll run out of first
What is the theoretical yield
amount of product calculated from a limiting reactant problem
what is the actual yield
the amount of product collected from the experiment
what is the % yield
the amount of the actual yield compared to the theoretical yield
what is the formula for percent composition
(number of atoms) (atomic weight) / Molar mass of the compound X100
what is a way you can remember the strong acids
So I Brought No CLean CLOthes
what is the first step of a limiting reactant problem
Calculate the moles of the product that can be
produced from the first reactant
what is the second step of a limiting reactant problem
Calculate the moles of the product that can be
produced from the second reactant.
how do you identify the limiting reactant in a problem
produces the least amount of product
what is the second step of a limiting reactant problem
Calculate the moles of product that can be
produced from the second reactant.
who created the law of conservation of mass theory
Antoine Lavoisier
Why do you care about yield?
This is the backbone
of the chemical and pharmaceutical industries.
who created the law of conservation of mass theory
Antoine lavoiser
