Is the following chemical equation as written consistent with the law of conservation of mass h so aq ca oh aq

m/z 1474.66) please predict its resulting m/z value after methyl esterification (assume that the reaction is complete) and calculate the corresponding b-type and y-type fragment ion series after this reaction. (10 pts) Part B: In order to distinguish the following two peptide sequences: NRNFLRFamide vs. GGRNFLRFamide, one can use formaldehyde reductive methylation. Please predict the al ion in both cases and outline main reasons that make this chemical reaction attractive ization for peptide de novo sequencing. (5 pts)

quid with a “sweet” smell. i. Using the ground state electron configuration and excited state electron configuration explain the hybridization of the central Carbon (C) atom. (7 Marks) ii. Identify the orbitals that overlap to form the C-Cl bond. Draw a diagram to show the orbital overlap. (3 Marks) iii. What is the bond angle of CCl4? (1 Mark) b) Consider a Fluorine atom (F) and a Fluorine anion (F-). Which of these two species would you expect to have a larger radius? Explain your answer. (5 Marks) c) Explain why the first ionization energy of Aluminum (Al) is less than that of Magnesium (Mg). (4 Marks) d) Assume the atom Oxygen(O) can form both cationic(O+) and anionic(O-) species. Place the following species in order of increasing first ionization energy, starting with the lowest. O+, O, O- (5 Marks) 4. a) Sea water contains roughly 28.0 g of NaCl per liter. (NaCl molar mass = 58.44 gmol-1). i. Calculate the number of moles of NaCl in a liter of sea water. (2 Marks) ii. Calculate the molarity of NaCl in sea water. (4 Marks) iii. Calculate the mass by volume percent (W/V) of NaCl in sea water. (4 Marks) Lowest first ionization energy ………………… ….. Intermediate ionization energy ………………… ….. Highest first ionization energy …………………

What will be the coefficient in front of CO in the balanced chemical equation? If there is no coefficient in front of CO in the balanced equation, enter 1 as the answer.

er choices Heat is generated when a solid is dissolved in a liquid None of these Two liquids are mixed and the resulting solution grows cold Bubbles formed in a liquid when heated A solid substance glows cherry red when heated

titrated with a 0.200 M solution of the base, LiOH. Write the balanced chemical reaction for neutralization reaction: HClO4 (aq) + LiOH (aq) → LiClO4 (aq) + H2O (l) Write the NET ionic equation for the neutralization reaction. OH⁻ (aq) + H⁺ (aq) → H2O (l) Compute the pH of the titration solution. Show your work i) before any of the base is added ii) after 25. mL of base is added iii) after 50. mL of base is added A student performs the titration with the same chemicals but with smaller volumes of each chemical . Which of the following titration curves could represent the titration. Explain A because this entails a strong acid and a strong base. Question 2 A student performs a titration of an unknown acid with a strong base and gets the following titration curve: a) The student consults the list of pKa of acids shown below. If the acid is listed in the table below, which is the most likely identity of the unknown acid? Explain. Acid Ka HF 7.2 x 10-4 CH3COOH 1.8 x 10-5 H2CO3 4.3 x 10-7 HBrO 2.0 x 10-9 The unknown acid is HBrO because the calculated Ka is in between 50^-4 and 50^-6 and 2.0 x 10^-9 lies in between them. b) What is the initial molarity of the acid? 10^-3 = 0.001M Question 3 a) Describe the components and the composition of an effective buffer solution. Explain how the components of the buffer allow the buffer to maintain its pH. An effective buffer solution has a weak acid and its conjugate base or a weak base and its conjugate acid. A buffer solution is most effective when the ratio of its component concentrations is close to 1, also when the pH is equal to the pka of the acid.; The components of the buffer allow the buffer to maintain its pH because buffers can absorb excess H+ions or OH– ions. An employer is interviewing four applicants for a job as a laboratory technician and asks each how to prepare a buffer solution with a pH of 5.0. The following constants may be helpful: hydrazoic acid, pKa = 4.74 Boric acid, pKa = 9.23 Archita A. says she would mix equal molar solutions of hydrazoic (HN3) and sodium azide (NaN3) solutions. Bradley B. says she would mix equimolar Boric acid (H3BO3) and HCl solutions. Carlos C. says he would mix equimolar Boric Acid (H3BO3) and sodium dihydrogen borate (NaH2BO3) solutions. Delia D. says he would mix equimolar hydrazoic Acid (HN3) and NaOH solutions. b) Which of these applicants has given an appropriate procedure? Explain your answer Delia because she is using Sodium hydroxide which results in a pH of 5. NaOH is a strong base and in order to have an effective buffer a weak acid must be incorporated which is the HN3. c) Explain what is wrong with the erroneous procedures. The rest all incorporate a strong acid and a strong base or a weak acid and a weak base which don’ result in an effective buffer. d) The applicants have access to the 1 Liter volumes of each of the solutions listed above. They have access to graduated cylinders. In order to make 1.0 Liter of the correct 5.0 buffer solution, what volumes of the two chemicals must be mixed?

mixed with 56.0 grams of N2, how many moles of the excess reagent would remain upon completion of the reaction? That is, how many moles of H2 or N2 will be left after the limiting reactant is entirely consumed?

SWER TO EACH QUESTION ON THE APPROPRIATE LINE ON THE ANSWER SHEET. FOR OTHER QUESTIONS, CLEARLY WRITE THE ANSWER, INCLUDING UNITS WHEN NECESSARY, ON THE ANSWER SHEET. SHOW ALL WORK ON A SEPARATE SHEET OF PAPER. HAND IN ASSIGNMENT, ANSWER SHEET, AND SCRAP WORK. 1. How many valence electrons are expected for an element that is in group 15/5A of the periodic table? A. two B. three C. five D. eight E. ten 2. Which of the following pairs of bonded atoms would be expected to have the longest bond length? A. C  N B. C  S C. C  B D. C  Fsdfasdfas