Tutor profile: Vivian C.
Subject: Organic Chemistry
Rank these nucleophiles in order of reactivity from strongest to weakest nucleophile and explain: water, Cl-, CN-, ammonia.
1. CN- 2. Cl- 3. ammonia (NH3) 4. water (H2O) The following four factors dictate nucleophilicity: 1. Charge - as the density of a negative charge increases, nucleophilicity increases. 2. Electronegativity - very electronegative atoms are poor nucleophiles because they don't want to share their electrons. As electronegativity increases, nucleophilicity decreases. The order of electronegativity is C< N < O < F 3. Steric Hindrance - the bulkier a nucleophile is, the harder it is to attack an electophile. 4. Effect of solvent (this isn't relevant for this questions). CN-, and Cl- are the three most reactive because they have a negative charge. CN- is the more reactive because the negative charge is on carbon and carbon is less electronegative than Cl- and thus more unstable. Ammonia is more reactive than Water because Nitrogen is less electronegative than Oxygen and thus more willing to share its electrons.
Compare the structure and functions of DNA and RNA
The structure of DNA and RNA Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) are both nucleic acids that are made up of nucleotides. DNA is a double-stranded molecule made up of nucleotides known as a double helix, RNA is a single-stranded molecule made up of nucleotides. Each nucleotide has the following three components: a 5-carbon sugar molecule, a phosphate group, and a Nitrogen base. DNA and RNA are made up of different 5-carbon sugars. DNA’s 5-carbon sugar is deoxyribose while RNA’s sugar is ribose. These sugars and the phosphate group form a sugar-phosphate backbone in RNA and DNA. RNA and DNA have one different Nitrogen base. DNA contains cytosine, guanine, adenine, and thymine. RNA shares the first three Nitrogen bases but contains uracil instead of thymine. In summation both DNA and RNA are made up of nucleotides but they have three main structural differences (1) RNA is single-stranded while DNA is double-stranded (2) RNA’s sugar is ribose while DNA’s sugar is deoxyribose (3) DNA contains thymine and RNA contains uracil (CrashCourse, 2012). The function of DNA and RNA DNA and RNA both carry genetic material however DNA carries the genetic code for living organisms while RNA is involved in protein synthesis, and regulation. DNA stays in the nucleus of an organism while RNA transfers genetic code from the nucleus to ribosomes to make proteins. DNA copies itself via replication in order to provide new cells with DNA, while RNA’s main function is to use the information stored in DNA to make proteins. DNA is copied into RNA via transcription and then RNA produces proteins via translation (LibreTexts, 2020). Works Cited: CrashCourse. (2012). DNA Structure and Replication: Crash Course Biology #10. YouTube. https://www.youtube.com/watch?v=8kK2zwjRV0M&t=546s LibreTexts. (2020, August 14). 3.4A: DNA and RNA. LibreTexts. https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/Book%3A_General_Bi ology_(Boundless)/03%3A_Biological_Macromolecules/3.4%3A_Nucleic_Acids/3.4A%3A_DNA _and_RNA
Josh and Casey both leave the concert at the same time. They need to walk in opposite directions to get home. If Casey travels 3 mph faster than Josh and after 2 hours they are 10 miles apart, how fast in mph is Casey traveling?
I know that distance equals rate times time so I will be using the formula d = rt to solve this problem. I organize my information below: Person. Rate (r) in miles. Time (t) in hours. Distance (d) in mph Josh r 2 2r Casey r + 3 2 2(r+3) To fill out the chart I used the following logic: I know that t = 2 because the word problem states “after 2 hours”. I used the variable “r” to represent the unknown rate. Josh's rate is “r” and Casey's is “r + 3”. Essentially Casey's rate will be Josh's rate plus 3 mph. The distance column I filled out using my formula “d = rt”. I used my chart to set up a formula to solve for the rate. The word problem told me that they are 10 miles apart, which means their total distance traveled will be 10 miles. I have both of their distances in my chart so all I need to do is add their distances to equal 10 miles. Step 1: Set up the equation. 2r + 2(r+3) = 10 Step 2: Apply the distributive property. 2r + 2r + 6 = 10 Step 3: Combine like terms. 4r + 6 = 10 Step 4: Use inverse operations to isolate the variable. 4r + 6 = 10 -6 -6 4r = 4 /4 /4 r = 1 R represents Josh's rate, to calculate Casye's rate I need to use the equation for Casey's rate from the chart. Casey's rate = r + 3 Plug in 1 for r Casey's rate = 1 + 3 Casey's rate = 4 mph FINAL ANSWER: Casey is traveling at 4 mph.
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