Chemistry 1310 - Out of Class Assignment #2

Chemistry 1310 - Out of Class Assignment #2: Fall 2021 (100 pts) Criteria: • You are to work alone, by yourself on this assignment. This is to be an individual effort! • Resources to use your notes, textbook, my power point slides and supplemental lecture notes and a periodic table. • Resources not to use are other students, the internet (i.e., Google Answers etc.), former instructors, family members, friends, tutors etc. • I will not help you solve or answer any questions about these problems nor will any of the faculty members in the Department of Chemistry & Biochemistry aid you with these problems. Reason: These are exam questions. o Failure to abide by these criteria will result in a grade of ZERO and will be reported to the Office of Student Affairs for violation of the University’s Academic Code of Honor. Directions • Please download and complete this worksheet. o When completed place in Dropbox under the designated heading. o Submit you work as Your LastName_Firstname-Worksheet1.docx • Watch the units and significant figures! • Place answers in blanks provided. • You must show calculation set-ups to receive full credit. o Only showing the answer or incomplete work will be grade at ½ or less credit. • Answer key will be posted in the OCA folder after the due date and time have passed. • Must be readable and legible, otherwise full credit will not be given, even if answer is correct. o PLEASE make sure when you scan in your work it is clear to read, right-side up and in order. THIS ASSIGNMENT IS DUE BY 10:00 PM ON WEDNESDAY NOVEMBER 3, 2021. 1. (14 pts) Jane and Judy have been assigned the task of determining the molarity of gastric juices. Stomach "acid" (i.e., gastric juice) is hydrochloric acid. A 15.0 ml of gastric juice sample was titrated with 0.0200 magnesium hydroxide solution. Judy determined it took 32.80 ml of the 0.0200 M magnesium hydroxide solution to reach the endpoint of the titration. Chemical reaction: hydrochloric acid (aq) + magnesium hydroxide (aq) → magnesium chloride (aq) + water (l) a. (4 pts) Using chemical formulas, write a balanced chemical equation for this reaction. b. (4 pts) Write a net ionic for this chemical reaction. c. (6 pts) Determine the molar concentration (M) for hydrochloric acid present in the gastric juice sample. 2. (13 pts) Given the following molecules: N2O PO2+ a. (9 pts) Draw a Lewis structure for each compound. N2O PO2+ b. ClO2ClO2- (4 pts) Determine which of these chemical species, if any, have the SAME electron pair (family) and molecular (shape) geometries. Identify the electron pair and molecular geometries. a. Specie(s) with same electron pair and molecular geometries. i. Identify the electron pair geometry: ___________________________________ ii. Identify the molecular geometry: b. c. ___________________________________ Specie(s) that do not have the same electron pair and molecular geometries. i. Identify the electron pair geometry: ___________________________________ ii. Identify the molecular geometry: ___________________________________ 3.(27 pts) The alcohol content of hard liquor is given in terms of “proof.” Proof is defined as twice the percent by volume (v/v) of ethanol (CH3CH2OH) in water. RJ’s new brew, Ginebra is 86% proof. Must show work to receive full credit. Useful Information: • A fifth is equivalent to 751.9 mL. • The density of pure ethanol is 0.789 g/mL • The density of water at room temperature is 0.9987 g/mL • The density of the ginebra solution is 0.995 g/mL. For the fifth of Ginebra (ethanol-water solution), determine the: a. 86.0% proof = _________________________ (v/v) % b. Volume of solute in a fifth _________________________ mL c. Mass of solute in a fifth _________________________ g d. Mass of solution in a fifth _________________________ g e. Mass of solvent in a fifth _________________________ g f. percent mass (w/w) % _________________________ (w/w) % g. mole fraction of solvent _________________________ h. percent (w/v) % _________________________ (w/v) % i. molal of the solution _________________________ m 4. (22 pts) Below is kinetic data gathered for the reaction: NH4+ + NO2- → N2 + 2 H2O Exp# [NH4+] [NO2-] initial rate (M/sec) 1 0.10 0.005 1.35 x 10-7 2 0.10 0.010 2.70 X 10-7 3 0.20 0.010 5.40 X 10-7 Based on this data determine: MUST SHOW WORK OR INDICATE REASONING ON HOW RATE ORDERS WERE DETERMINED. NO WORK FULL CREDIT. a. (6 pts) rate order for NH4+: __________________________________ b. (6 pts) rate order for NO2-: __________________________________ c. (4 pts) the rate law for the reaction: __________________________________ d. (3 pts) overall rate order of the reaction: __________________________________ e. (3 pts) units for the rate constant, k for the reaction: __________________________________ 5. (3 pts) Lattice energy is energy associated with the formation of an ionic solid crystal. Which of the following represents lattice energy? a. X3+ (g) + 3 A- (g) → XA3 (s) b. X (s) + 3 A2 (g) ➔ XA3 (s) c. 3 A (g) + 3e- + X3+ (g) → XA3 (s) Pressure 6. (7 pts) Given the following phase diagram, indicate the phase(s) for each letter. A. _________________________ B. _________________________ C. _________________________ D. _________________________ E. _________________________ F. _________________________ 7. (14 pts) Short Answer a. Soda-lime glass trade name is ________________________ b. T or F: KCl lattice energy is greater than KF lattice energy because fluoride ion has a greater electronegativity. c. Ceramic materials are inorganic powered solids. Kaloinite is a type of ________________ ceramic material whereas silicon carbide is classified as a ____________________ type of ceramic material. d. Who discovered the binding material we call cement ?_________________________. e. T or F: Concrete is cement. f. How are crystalline solids classified? ________________________________________________ g. List the two most common allotropes of carbon __________________________________________ h. Carbon nanotubes and dry ice are both crystalline solids. What is their classification designations? i. Carbon nanotubes: ________________________ ii. Dry ice: ________________________ i. How is electron movement increased in metallic solid conduction band? ______________________ j. __________________________ are materials where little if no electrons are present in a metal solid’s conduction band at room temperatures.