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Tutor profile: Danirys P.

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Danirys P.
Teacher of organic chemistry
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Questions

Subject: Organic Chemistry

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Question:

When 1-butene (C4H8) reacts with hydrogen chloride (HCl), the product is 2-chlorobutane and not 1-chlorobutane. Explain why.

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Danirys P.
Answer:

The reaction of 1-butene and HCl is an addition reaction to the carbon-carbon double bond. The reaction occurs at the double bond, the molecule that is added (HCl) binds to the carbons of the double bond. Due to the polarity of the H-Cl bond, H acts as an electrophile (H +) and Cl acts as a nucleophile (Cl-). The HCl addition reaction to 1-butene complies with the Markovnikov orientation: "the electrophile always binds to the least-substituted double-bonded carbon". This is possible because the pair of electrons in the pi bond of the double bond accepts the electrophile, it binds to the least substituted carbon and a carbocation (carbonium ion) forms on the other carbon of the double bond, which is more substituted or surrounded by radical groups. In this reaction, H + acts as an electrophile and will bind to carbon 1 (less substituted) and a positive charge will remain in carbon 2 (carbonium ion 2 °) that is more stable. This carbonium ion has a sextet and not an electron octet. Therefore, it will react with Cl- which will act as a nucleophile and 2-chlorobutane will be formed. For all of the above, the formation of 1-chlorobutane is not favored because the 1st carbonium ion that would be formed if the positive charge remained on carbon 1 is not the most stable:

Subject: Nutrition

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Question:

What is the difference between fortification and enrichment of foods?

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Danirys P.
Answer:

The terms fortification or enrichment indicate that nutrients (calcium, vitamin C, potassium, iron, protein or fiber) have been added to foods during the manufacturing process to improve their nutritional quality and provide benefits with minimal risk to health, respecting the food regulations. Generally, both terms are used as synonyms, and referred to as the addition of nutrients to a food regardless of whether or not they were present in the food and enrichment is referred to as a form of fortification. FAO (1994) defines fortification as the addition of one or more essential nutrients in order to prevent or correct its deficiency in food. It is considered the easiest, cheapest and most useful procedure to reduce, in particular the deficiency of folic acid, vitamins (A, C, D and B complex), niacin, thiamine, riboflavin, minerals (iodine, zinc, calcium and iron). It is also used when you want to improve the nutritional quality of a protein, which already contains the food, it is fortified by adding certain amounts of the limiting amino acid, which is generally lysine, methionine, tyrosine or tryptophan. Fortification is an added value that the food manufacturer wants to give to their product, there are laws that regulate the use of food as a vehicle to increase the intake of one or more nutrients by the population. For example, this is the case of salt to which since 1993 the World Health Organization and UNICEF have implemented a plan for iodization of salt as a way to avoid mineral deficiency. For its part, enrichment is defined as the process of restoring the nutrients that have been removed during food processing in accordance with the provisions of food regulations; for example, the addition of vitamin B1 to whole wheat flour to restore the level of said vitamin, in order to obtain a product with nutritional values similar to those it has in its less processed version.

Subject: Chemistry

TutorMe
Question:

Why can't the hydrogen (H2) molecule present the hydrogen bond? What type of bond is present in this molecule?

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Danirys P.
Answer:

In the hydrogen (H2) molecule, the bond that appears is the covalent bond that is what holds both hydrogen atoms (H-H) together. The hydrogen bond is a relatively weak attractive force between two dipoles (δ). The positive partial charge of H (δ +) of a molecule with polar bonds of the HO, HN and HF type is attracted by the negative partial charge ( δ-) of more electronegative atoms like O, N, F of another molecule. Within the same molecule, the hydrogen bond is not considered as a covalent bond, in the case of the hydrogen molecule, dipoles cannot be formed because they do not none of the electronegative atoms mentioned exist in the molecule

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