Tutor profile: Jack Z.
Subject: Organic Chemistry
What is the stereochemistry of a compound if an Sn1 reaction occurs at the chiral carbon if the substituted compounds is different from the other attached compounds? a) achiral b) same stereochemistry c) opposite stereochemistry d) racemic mixture
d) Achiral would indicate that 2 of the 4 compounds attached to the chiral carbon is the same. B and C is incorrect as Sn1 occurs in 2 steps and forms a planar intermediate, therefore, there is no definitive maintenance/change of stereochemistry. Therefore, D is correct.
What is the distinctive feature of a hemiacetal? a) a positive benedict test b) a negative benedict test c) a 1-4 glycosidic bond d) a 1-6 glycosidic bond
a) A hemiacetal is a reducing sugar, therefore the benedict test will be positive. A 1-4 glycosidic bond is not distinctive for a hemiacetal and nor is the 1-6 glycosidic bond.
When selecting a model for use, what should be the most crucial aspect to account for in a sample size of n=500? a) degrees of freedom b) maximum likelihood c) over-fitting
c) over-fitting is the most important aspect of model building for a statistical model to account for. In the case of a large sample, degrees of freedom is often not as crucial. In fact, in certain times, DoF can mislead individuals to falsely accepting/rejecting the null. Maximum likelihood is an important aspect of model building but plays more of a role in determining which model most fits the data that is presented and is not a factor to account for. Over-fitting is the most crucial aspect to account for as over-fitting the data may result in the inflexibility of the model in predicting new data that deviates from the original.
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