Tutor profile: Sarah L.

What is the difference between an SN1 reaction and an SN2 reaction?

An SN1 reaction is a unimolecular nucleophilic substitution reaction which involves a carbocation. This reaction occurs in two steps when there is more steric hindrance and/or the carbocation is stable. An SN2 reaction is a bimolecular nucleophilic substitution reaction in which a nucleophile replaces a leaving group. This reaction does not involve a carbocation and can only occur when the target atom is not sterically hindered. In certain cases, the identity of the solvent used in the reaction determines whether the reaction proceeds via an SN1 or SN2 mechanism.

What is the difference between an exothermic and endothermic process? Give an example of each.

An exothermic process involves the release of thermal energy while an endothermic process involves the input of thermal energy. An example of an exothermic process is water freezing, and an example of an endothermic process is water melting.

Explain the difference between a covalent and ionic bond.

A covalent bond consists of two atoms sharing electrons either equally or unequally. A polar covalent bond is a bond where the electrons are shared unequally, so one atom pulls more strongly on the electrons than the other. A nonpolar covalent bond is a bond where the electrons are shared equally, and both atoms pull equally strongly on the electrons. An ionic bond consists of one atom donating one or more electrons to another atom.