T/f Flashcards
Steric effect is mutual repulsion of atoms having inert gas configuration of electrons
True
A Lewis acid accepts a pair of electrons
True
Changing all of the stereogenic centers (e.g. R to S) in a chiral molecule will give a diastereomer
False but it will give an enantiomer
A meso compound has stereogenic centers
True
The atomic number of beryllium is 5
False
Resonance forms are structures of rapidly interconverting molecules
False
A chiral reagent or method is always required to recognize/separate enantiomers
True
Z-2,3-dibromo-2-butane and E-2,3-dibromo-2-butane are disatereomers
True
The density of substances which gloat on water is usually less than 1.0
True
Intermolecular attraction of alkanes molecules is due to London forces
True
Delta G is positive for an endothermic reaction
True
Amide anion (NH2 minus) is less basic than hydroxide anion
True
About 150 to 200 kcal/mole of energy are available at toom temperature
False
The net dipole of dichloromethane is aligned with a carbon-chlorine bond
False
A completely pure organic combined may have different physical properties depending on whether it was made by chemists or isolated from nature
False
Bronsted- Lowry acids donate a proton
True
A carbocation intermediate in a reaction is a transition state
False
The pKa of pure water is about 7
False
The structure of a molecule determines all of its physical and biological properties
True
Overlap of two sp2 orbitals in a double bond generates a sigma molecular orbital
True
A Lewis acid is a nucleophile
False
Changing all of the chiral centers (e.g R to S) in a chiral molecule will give an enantiomer
True
A meso compound is achiral
True
A 80:20 mixture of enantiomers has an optical purity of 60%
True
A 80:20 mixture of enantiomers has an enantiomeric excess of 60%
True
A chiral reagent or method is always required to separate enantiomers
True
The S,2 reaction has a carbocation intermediate
False
Delta G is negative for an endothermic reaction
False
Resonance forms are not rapidly interconverting molecules
True
Resonance forms are structures of rapidly interconverting molecules
False
Compounds containing more than 65% halogen usually have a density rho > 1.0
True
The atomic number of an atom is the total mass of neutrons and protons in the nucleus
False
A radical intermediate in a reaction is accurately described as a transition state
False
The net dipole of chloroform is not aligned with any carbon-chlorine bond
True
Elemental Iodine (I2) reacts slowly with alkanes to give alkyl iodides
False
The energy needed to break a carbon-hydrogen single bond is about 15-20 kcal/mole
False
All Bronsted-Lowry acids are also Lewis acids
True
The net dipole of carbon tetrachloride is zero
True
Overlap of two sp orbitals in a triple bond generates a sigma molecular orbital
True
The energy needed to break a carbon-hydrogen single bond is about 100 kcal/mole
True
Chloroform has a density r > 1.0
True
The net dipole of methane is zero
True
Cis- 1,2 - dichlorocyclopropane and trans-1,2,- dichlorocyclopropane are diastereomers
True
Tautomers are structural isomers with respect to each other
True
The atomic number of an atom is the total number of protons and neutrons in the nucleus
False
The E1 reaction has a carbocation intermediate
True
The zaitsev (saytzeff) rule factors formation of more highly substituted double bonds
True
Oxidation is always defines as the process of adding oxygen atoms
False
