Ex.1 Feb 19 .2020 w Answers.pdf - 030.102.01 Introductory...

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030.102.01, Introductory Chemistry II, Section 1, Spring 2020 Midterm Exam I , Feb. 19, 2020 Prof. K. D. Karlin page 1 of 4 (plus Table) Name :____ ANSWERS _______________ Total points possible: 100 Print Clearly Student ID # :____________________ * Answer all questions, preferably IN INK. * Partial credit may be given for questions if work is shown Miscellaneous information: [H 3 O + ]= K a x [Acid]/[Conjugate-Base] R = 8.315 joules/mol-K = 1.987 cal/mol-K pH = –log[H + ] K w = 10 –14 D G ° = –n F E ° = – R T ln K eq E cell = E cell ° – 0.0591/n log 10 Q E cell = E cell ° –2.303 RT/n F log 10 Q Faraday constant F = 96,500 Coulombs/mol 1 joule = 1 coulomb x 1 volt TOTAL: pH = pK a - log [Acid] [Conj. base] Max. points Points received 1 7 2 7 3 12 4 12 5 12 6 12 7 12 8 16 9 10
030.102.01, Introductory Chemistry, Section 1, Spring 2020 page 2 of 4 (plus Table) Midterm Exam I, Feb. 19, 2020 Prof. K. D. Karlin Name of Student ___ ANSWERS 1.(7)Which one of the following substances is never a Brønsted-Lowry acid in an aqueous solution? a) hydrogen fluoride, HF(g)b) sodium phosphate, Na3PO4(s)c) hydrogen bromide, HBr(g)d) ammonium chloride, NH4Cl(s)e) sodium bicarbonate, NaHCO3(s)Answer___b____ 2. (7)From the following list of molecules and ions which two behave as Lewis bases: H2O, F, BH3, Fea) H2O and Fb) Fand BH3 c) BH3and Fe3+d) H2O and Fe3+ e) Fand FeAnswer ___ a____ 3.(12)Calculate the [H3O+] during the titration of 30.00 mL of 0.50 M nitrous acid (HNO2, Ka = 4.5 x 10–4 3+ 3+ ) 2

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