Mod 4 moles and compounds Flashcards
To convert mass to moles or moles to mass, we use the mole relationship: ____ mole of a substance = molar mass of the substance.
1
To figure out the amount of each reactant or product in a reaction, we apply ____________.
stoichiometry
stoichiometry allows chemists to predict the following:
the amounts of products that form in a chemical reaction based on the amounts of reactants
how much of the reactants are necessary to form a given amount of a product
how much of one reactant is required to completely react with another reactant
The ________________ or _________________ is the reactant that is completely used up in a reaction. It is important to note that in some cases, all the reactants are completely used up. When that happens, the reactants are said to be in _____________ amounts.
Limiting reactant or limiting reagent
stoichiometric
The following rules can be applied to identify
I) If there is only one reactant (i.e. a decomposition reaction), that reactant is the limiting reactant.
II) If two or more reactants are used but quantities are provided for only one reactant, the reactant whose quantity is provided is the limiting reactant.
III) If the quantities are provided for two or more reactants, we need to calculate the quantities required and compare them with the amounts provided in order to determine which reactant is the limiting reactant.
the limiting reactant
The maximum calculated amount of product formed from the limiting reactant is called the ______________. reported in percentages
theoretical yield
the ____________ is the maximum amount of a product possible in a reaction. If the actual yield is more than the theoretical yield, we would be violating the ______________________.
theoretical yield
law of conservation of mass.
_____________ is the determination of the Heat Absorbed or Released in a Reaction
Thermochemistry
When describing heat loss or gain there are two terms that we should be familiar with: system and surroundings. The______________ is whatever is being observed and the _______________ are everything else.
system
surroundings
formula mass depends on whether the element is monatomic or diatomic.
For monatomic elements, the formula mass is its _______ _______ found on the periodic table. For diatomic molecules, the formula mass is calculated by multiplying the ________ _________ by 2.
atomic mass
atomic mass
Whats the formula mass of Oxygen? How did you calculate it?
32.00 amu
because the formula mass for a diatomic molecule is 2x the atomic mass on the periodic table.
therefore 2*16.00 amu = 32.00 amu
_______________ is equal to the sum of the average atomic masses of these atoms making up the molecule.
formula mass
to calculate formula mass of a molecular compound (also called molecular mass) ________ the atomic masses of each element that makes up the molecule.
add
= 119.37 amu
How do you calculate the formula mass of an ionic compound? Why?
The same way you calculate the formula mass for molecular compounds.
Sum the average atomic masses (use the periodic table) of all the atoms in the compound’s formula.
The formula for an ionic compound is the ratio of the cations to the anions.
Because the formula for an ionic compound does not represent the composition of a discrete (isolated) molecules as with molecular compounds.
T/F the formula mass of N2O5 is 108.02
What are the 7 diatomic molecules?
hydrogen (H),
nitrogen (N),
oxygen (O),
fluorine (F),
chlorine (Cl),
bromine (Br),
iodine (I).
“Hi BrO is Florine n Chlorine???”
an ionic compound is the result of a ________ and ________ combining which forms an ionic bond between the atoms.
metal
non metal
Chemistry uses a unit called the mole. A ________ (abbreviated as mol) is defined as exactly 6.02214076×1023 things.
mole
The numerical value of things in a mole is refered to as _____________ number or ___________________ constant.
Avogadro’s number or Avogadro’s constant
What is the molar mass of CHCl3?
the Molar mass is 119.37 g/mol
The first conversion factor converts _______ to ________.
The second converts __________ to __________.
grams to moles
moles to grams
(whatever unit is the numerator is what you’re converting to!! and denominator is what your converting from!!))
Avogadro’s number can be used to convert between the ________ of individual particles and the number of ________ in a substance.
number
moles
check all that apply
The first two answer are correct.
When using the proper conversion factors you convert 0.162 moles to atoms using avogado’s constant
next you convert 0.162 moles of silver to grams using the atomic mass of silver found on the periodic table. The atomic mass of silver is 107.87amu. remember THE MOLAR MASS IS THE SAME AS ATOMIC MASS EXPRESSED IN GRAMS INSTEAD OF AMU.
This formula calculates the __________ percent.
The mass percent composition, or mass percent.
The mass percent of an element, is the element’s percentage of the total mass of the compound
When calculating mass percent, either the actual mass of the element or the atomic mass can be used in the calculation. Examples are shown below.
______ ________ __________ can be used as a conversion factor between grams of a constituent element and grams of the compound. For this, we assume that we have _____________ of the compound.
mass percent composition
100.00 grams
Whats the mass percent of chlorine in aluminum chloride?
get the formula for alcl
then calculate the amu of the compound.
amu cl/total amu of alcl *100 = mass percent of chlorine in aluminum chlorine
3
B
C
B
