Chem 1411 Final Review
A tank containing both HF and HBr gases developed a leak. The ratio of the rate of effusion of HF to the rate of HBr is
2.01
How many polar bonds does CCI4 have in its structure?
4
The halogens have how many valence electrons?
7
What is the pressure for STP conditions?
760 mm Hg
The octet rule states that main group elements in the periodic table react to achieve a filled valence shell which consists of how many electrons?
8
Based off periodic trends, which of the following has the strongest lattice energy?
Aluminum chloride
What instrument is used to measure atmospheric pressure specifically in the area of meteorology?
Barometer
What substance would be a poor choice for making conductive solutions?
C6H12O6, CH3OH, CH3Ch2OH
According to VSEPR theory, the shape of an ammonium ion, NH4+, is most similar to
CH4
Which alkane would have a lower boiling point?
CH4
The bond angles in CH4, Nh3, H2O are 109.5, 107 and 104.5 respectfully. Which of the statements best describes the variance in bond angles?
CH4 has no lone pairs of electrons on the central atom so the optimal molecular shape would be tetrahedrale with bond angles of 109.5. In NH3 and H2O there are 1 and 2 lone pairs, respectfully, so more repulsion exists between the bonds and lone pairs as a result the bond angles are less than 109.5
On a very cold day, you notice that your tires look a bit deflated than warmer days. This observation can be explained by
Charles Law
What is the electron group and molecular geometry of an ammonium ion?
EG & MG tetrahedral
What is the EG and MG of an ammonia molecule?
EG tetrahedral and MG trigonal pyramidal
Which statement best describes a bond forming between fluorine and iodine?
Fluorine is more electronegative than iodine so it will attract the electron density in the bond giving rise to a polar bond.
Which phases change is an exothermic process?
Freezing
Which of the following halogens would have a stronger intermolecular forces?
I2
Which of the following molecules would have weaker intermolecular forces?
I2
Construct the molecule IF5 and PF5. How do the molecular shapes differ?
In IF5 there is a lone pair of electrons on iodine where as in a PF5 there are no lone pairs on phosphorus. As a result, the molecular shape of IF5 is square pyramidal and PF5 is trigonal bipyramidal.
Using VSEPR theory, predict the molecule shape of a molecule that contains 2 electron groups.
Linear
What predominate intermolecular force is in CO2?
London-forces
Which of the following pairs of elements can be joined by a covalent bond?
N and C
A diatomic molecule with a triple covalent bond is
N2
Which of the following molecules has the greatest bond energy?
N2
Which of the following is an iconic compound?
Na2O
Which of the following would conduct electricity?
NaCl solution
Using VSEPR theory, predict the electron group geometry, molecular shape and the bond angles in a molecule that contains 4 electron groups (3 bonds and 1 lone pair).
Tetrahedral, trigonal pyramidal, <109.5
Which statement best describes the structure of a carbonate anion?
The electron geometry of carbon in a carbonate anion is trigonal planar with a sp2 hybridization and bond angles are 120. There is a pi-bond formed between a non-hybridized "c" p-orbital overlapping with an "O" p-orbital.
Based on the valence bond theory, which statement best describes the electron geometry, bonding and hybridization of the central atom in carbon tetrachloride?
The electron geometry of carbon tetrachloride is tetrahedral with a sp3 hybridzation. The C-Cl bond is a (std. dev) character.
Based on valence bond theory, which statement best describes the electron geometry and hybridization of the central atom in acetylene, H2C=Ch2?
The electron geometry of the 2 carbons in acetylene is linear with the sp hybridization.
Which statement accurately depicts what happens to water on the molecular level in a tea pot when it begins to boil?
The molecules begin to move farther apart decreasing their intermolecular forces and they escape the liquid state to enter the gas state.
Using VSEPR theory, predict the electron group geometry, molecular shape and the bond angles in a molecule that contains 5 electron groups (2 bonds and 3 lone pairs)
Trigonal bipyramidal, linear and 180
Using VSEPR theory, predict the molecular shape and bond angles in BCI3
Trigonal planar, 120
If you want to boil a pot of water containing salt, what temperature would the boil begin?
above 100 degree C
Which of the following would be a weak electrolyte in solution?
acetic acid
On a hot summer day, you notice that a bag of chips left in your car has inflated. Why did this happen?
as temperature increases, gas molecules gain kinetic energy and the volume of gas increases inside the bag of chips.
What is the relationship between pressure and volume of a gas at a constant temperature?
as volume decreases, pressure increases
What temperature does salt water freeze?
below 0 degree C
Based on valence bond theory, what is the hybridization of the central atom in C2F4?
both carbons are sp2
What predominate intermolecular force is in HCl?
dipole-dipole
According to the octet rule, a bromine atom has a tendency to
gain one electron
Based off the molecular polarity of water, which of the following molecules would be soluble in water?
glucose, methanol and ethanol.
What predominate intermolecular force is in Ch3OH?
hydrogen bonding
What is the molecular shape of CO2?
linear
What predominate intermolecular force is in CH3Ch2Ch3?
london forces
According to the octet rule, a magensium atom has a tendency to
lose two electrons
Water changing from ice to liquid is an example of
melting
A covalent bond is formed when two atoms
share one or more pairs of electrons with each other
What is the molecular shape and polarity for xenon tetrafluoride?
square-planar and non polar
Sodium chloride changing from a solid to a gas is an example of
sublimation
Which of the following when dissolved in deionized water would make a poor conducting solution?
sugar
What solution would be soluble in water?
sugar, NaCl, HCl