Tutor profile: Isheeta T.
Subject: Organic Chemistry
What type of reaction is this and what is the product? (R) 2-bromobutane + Potassium cyanide. Solvent: acetone.
This is a SN2 reaction. We start with a strong nucleophile (CN), which indicates a substitution reaction over an elimination reaction. We have a good leaving group (bromine) which is stable once is leaves. Since we have a strong nucleophile and a good leaving group, this indicates a SN2 reaction over an SN1. There is not much steric hindrance so a bimolecular reaction is possible here. We have a polar aprotic solvent, which means the solvent does not engage in hydrogen bonding. Since this is a bimolecular reaction, we do not need hydrogen bonding to stabilize the intermediates. All of these indicate that the most likely reaction is SN2. In an SN2 reaction, the product goes through inversion of configuration which means that our product will be (S) since our reactant is (R). The final product is (S) 2-cyanobutane.
Subject: Basic Chemistry
Describe the difference between covalent and ionic bonds.
A covalent bond is formed when the two electrons in the bond are shared between two atoms. This can occur two ways: one atom donates both electrons to the bond or each atom donates one electron each to the bond. Covalent bonds are between non-metals. An ionic bond electrons are "held" by one atom. This creates a negative and positive charge which helps the atoms stay attracted to each other. Ionic bonds are between metals and non metals.
In what stage of meiosis does crossing over occur?
Crossing over is the exchange and swap of genetic material between sister chromatids. This occurs during Prophase 1 of Meiosis when the chromosomes condense.
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