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Compounds
They can be separated into elements by chemical changes
Mixtures
can be separated by physical changes and based on differences in particle size, the larger one is trapped on the filter paper
Distillation
separates mixtures based on differences in boiling points
Chromatography
separates mixtures based on differences in polarity
Paper chromatography
the component that is most similar in polarity to the mobile phase moves up the farthest.
When is mass converted?
during chemical and physical change
Reading the volume of a liquid in a container
you can estimate It by looking in between the gradual markings and this can give you one more sig fig
Least precise measurement to more precise measurement
beaker, graduated cylinder, volumetric flasks, burette. (volumetric flash has one line on it to measure specific volume)
What does density equal?
mass/volume
What doesn’t change for a pure compound?
the % composition by mass
When an electron is in a higher energy level
it is farther away from the nucleus and has less Coulumbic attraction
Moving across a row on the periodic table
The Zeef(effective nuclear charge) increases and the valence electrons are more attracted to the nucleus
When reading a PES graph
the higher the peak, the more electrons there are in that sublevel and a larger binding energy
When writing the electron configuration for a cation
remove the valence electrons first
Isotopes of an element
have the same number of protons but different numbers of neutrons
Mass spectroscopy
graphs measure atomic masses of isotops
Elements in the same group
have similar chemical and physical properties
Metals are on the
left side of the zig zag line
Non metals are on the
right side of this line of the periodic table
Cations(+) are smaller than their atoms
because you are removing valence electrons that are farther from the nucleus
anions(-) are larger than their atoms
since adding extra electrons increases electron-electron repulsion
Covalent bonds form between
two nonmetals sharing electrons
Ionic bonds are formed when
a metal transfers electrons to a nonmetal and the opposite charges attract
The greater the electronegativity difference
the more polar the bond becomes
Combustion reactions make
CO2 and H2O
Diatomic elements
H O N Cl Br I F
Empirical formula rhyme
% to mass, mass to mole, divide by small, time until whole
% yield
experimental/theoretical
% error
(experimental - theoretical)/theoretical
The amount of production for a reaction is determined by
the limiting reactants
Why are gas mixtures homogeneous?
because of the constant random motion of particles
Why are Gases compressible?
because of the large spaces between the particles
What is gas pressure caused by?
by the collisions of particles with the walls of the container. More collisions will mean more pressure
How are T and V related?
directly related (heat a balloon it will expand)
How are T and P related
directly related, heat a container and the pressure will increase
Gas constant R
0.08206
One mole of an ideal gas
22.4 L
How is gas pressure and number of moles related
directly related (double the moles and the pressure will double)
The more molar mass a gas will
move slower at a given temperature
Temperature =
Average Kinetic Energy
Gas by water displacement
Ptotal = Pdry gas + Pwater vapor
Real gases behave like
most ideal gas at high temperature and low pressure
The more polar and larger a gas is
it will deviate from ideal behavior
Small nonpolar gases are
the most ideal
Exothermic reactions are
H: it feels hot and heat is a product; temperature goes up (endothermic is the opposite)
Hrxn =
bonds broken- bonds formed
which bonds are broken and which are formed?
reactant bonds are broken and product bonds are formed
Breaking bonds
endothermic
Forming bonds
exothermic
Hrxn= Hproducts - Hreactants
multipl the coefficients as well!
exothermic reactions will result in
the bonds formed in the products are stronger/more stable than the reactant bonds
What will happen when you double a reactions
H will double
Reversing a reaction?
the sign for H changes
adding reactions?
add all the H’s
Carbon makes a total of how many bonds in compound?
4
4 domains angle
109.5
3 domains angle
120
2 domains angle
180
4 domains hybrid orbitals
sp3
3 domains hybrid orbitals
sp2
2 domains hybrid orbitals
sp
Are asymmetrical molecules nonpolar?
No because the dipoles do NOT cancel out
Are symmetrical molecules polar?
No because the dipoles cancel out
What is Lattice energy?
it is the energy to break an ionic bond in a compound.
When does Lattice energy increase?
It increases as the ion’s charge increases
When does Lattice energy decrease?
when the radii of the ions increase
What is formal charge
It involves comparing the number of valence electrons an atom has to the number of electron around it in the Lewis structure.
When to obey the octet rule
when first drawing the Lewis Dot Structure and then use formal charge if necessary
Where do the extra electrons go?
They can go on the larger central atom
When you have too few electrons?
start making some double or triple bonds
Note 
Flashcard (72)