True or False Flashcards
steric effect is mutual repulsion of atoms having inert gas configuration of electrons
T
A lewis acid accepts a pair of electrons
T
changing all of the stereogenic centers in a chiral molecule will give a diastereomer
F (it gives an enantiomer)
meso compounds have no enantiomer
T
the atomic number of beryllium is 5
F (it’s 4)
resonance forms are structures of rapidly interconverting molecules
F (definition of tautomers) resonance: diff drawings of the same molecule made by moving electrons but not atoms
a chiral reagent or method is always required to recognize enantiomers
T
a 60:40 mixture of enantiomers has an optical purity of 60%
F (it’s 20%)
the density of substances which float on water is usually greater than 1.0
F (substances that float on water has a density less than 1.0)
intermolecular attraction of alkane molecules is due to London forces
T
deltaG is positive for an exothermic reaction
F (it is negative)
hydroxide anion is less basic than amide anion
T
About 150-200 kcal/mole of energy are available at room temperature
F (15-20 kcal/mole of energy)
the net dipole of chloroform is aligned with a carbon-chlorine bond
F (idk man)
a completely pure organic compound may have different physical properties depending on whether it was made by chemists or isolated from nature
F
bronsted-lowry acids donate a proton
T
a radical intermediate in a reaction is a transition state
F
the pKa of water is about 7
F (pKa = ~16, pH = 7)
the structure of a molecule determines all of its physical and biological properties
T
overlap of two sp orbitals in a triple bond generates a pi molecular orbital
F (overlap of p atomic orbitals with s component fives pi molecular orbital)
enthalpy is negative for an exothermic reaction
T
chloroform has a density r > 1.0
T
elemental iodine reacts slowly with alkanes to give alkyl halides
F (iodine does not react)
the net dipole of methane is 0
T
the energy available to molecules at room temp is about 15-20kcal/mol
T
all lewis acids accept a pair of electrons
T
compounds containing more than 65% halogen usually have density r > 1.0
T
the net dipole of carbon tetrachloride is 0
T
overlap of two sp orbitals in a triple bonds generates a sigma molecular orbital
T
the energy needed to break a carbon-hydrogen bond is about 100 kcal/mole
T
all lewis acids are also bronsted lowry acids
F (all bronsted lowry acids are lewis acids)
the atomic number of an atom is the total mass of neutrons and protons in the nucleus
F (definition describes atomic weight) atomic number: number of protons in the nucleus of an atom
the net dipole of chloroform is not aligned with any carbon-chlorine bond
T
all bronsted lowry acids are also lewis acids
T
a lewis acid is a nucleophile
F (lewis acid accepts electron)
changing all of the chiral centers in a chiral molecule will give an enantiomer
T
a meso compound is achiral
T
a 80:20 mixture of enantiomers has an optical purity of 60%
T
a 80:20 mixture of enantiomers has an enantiomeric excess of 60%
T
the Sn2 reaction has a carbocation intermediate
F (no intermediates, Sn1 has a carbocation intermediate)
the density of substances that float on water is usually less than 1.0
T
resonance forms are not rapidly interconverting molecules
T
bronsted lowry acids donate a proton
T
cis-1,2- dichlorocyclopropane and trans-1,2-dichloropropane are diastereomers
T
tautomers are structural isomers with respect to each other
T (Tautomers are rapidly interconverting structural isomers)
the atomic number of an atom is the total number of protons and nucleus in the nucleus
F ( atomic number: number of protons in the nucleus of an atom)
the E1 reaction has a carbocation intermediate
T
the Zaitsev rule favors formation of more highly substituted double bonds
T
oxidation is always defines as the process of adding oxygen atoms
F (oxidation: lose electrons)
