Cheating Is Not Allowed. Anyone Caught Cheating Will Be Turned Over to Judicial Affairs

Name:______

CHEMISTRY 1211

EXAM #2

This exam is 9 pages long. Please read through all of the questions first and ask about anything you do not understand. You will have one hour and 15 minutes to complete this exam. Exams will be picked up at the end of the class period. No late exams will be accepted!

You are allowed to use a calculator. If you do not have a calculator, setting up the problem correctly will gain you some points but you will not receive full credit for any question you do not answer completely.

Included in this exam is a periodic table, which should be stapled to the back of the exam.

CHEATING IS NOT ALLOWED. ANYONE CAUGHT CHEATING WILL BE TURNED OVER TO JUDICIAL AFFAIRS.

The exam is worth a total of 100 points. Each question is labeled with its exact point value. Be sure to answer all of the questions on the exam.

Good Luck! 2

(5 points each) 1.)Write the balanced equation for the complete neutralization of dilute H3PO4 with Ca(OH)2 in aqueous solution. What is the sum of the coefficients? (Do not forget coefficients of one.)

a.) 10 b.) 12 c.) 14 d.) 16 e.) 18

2.) Will a precipitate form when 0.1 M aqueous solutions of CaCl2 and K2CO3 are mixed? If a precipitate does form identify the precipitate and give the net ionic equation for the reaction.

a.) No precipitate forms 2+ -2 b.) CaC2 precipitates Ca (aq) + 2CO3 (aq)  CaC2 (s) + 3 O2 (g) 2+ -2 c.) CaCO3 precipitates Ca (aq) + CO3 (aq)  CaCO3 (s) 2+ + d.) CaCO3 precipitates Ca (aq) + K2CO3 (aq)  CaCO3 (s) + 2K (aq) e.) KCl precipitates K+(aq) + Cl (aq)  KCl (s)

3.) Classify the following reaction by giving all of the reaction types that apply.

I.) redox II) combination III) decomposition IV) displacement

2H2O2 (aq)  2H2O(l) + O2 (g)

a.) I and III b.) only II c.) I and II d.) only IV 3

e.) III and IV

4.) How many mL of 18.4 M H2SO4 are needed to prepare 600. mL of 0.10 M H2SO4? a.) 1.8 mL b.) 2.7 mL c.) 3.3 mL d.) 4.0 mL e.) 4.6 mL

5.) What volume of 0.130 M HCl solution will just react with 0.424 grams of Ba(OH)2? Be sure to balance the equation.

HCl (aq) + Ba(OH)2 (s)  BaCl2 (aq) + H2O (l)

a.) 38.1 mL b.) 32.6 mL c.) 24.1 mL d.) 18.6 mL e.) 96.7 mL

6.) Calculate the molarity of a solution that contains 4.5 grams of (COOH)2 in 3000mL of solution.

a.) 0.033 M b.) 0.045 M c.) 0.017 M d.) 0.090 M e.) 0.12 M

7.) What volume of 0.122 M HCl would react with 26.2 mL of 0.176 M NaOH?

a.) 37.8 mL b.) 18.2 mL c.) 5.56 mL d.) 26.3 mL e.) 75.6 mL

8.) What is the molarity of a potassium hydroxide solution if 38.65 mL of the KOH solution is required to titrate 25.84 mL of 0.1982 M hydrobromic acid solution?

a.) 0.1325 M b.) 0.2963 M c.) 0.8817 M d.) 0.2648 M e.) 0.01324 M

9.) During a titration the point at which stoichiometrically equivalent amounts of acid and base have reacted is called the ______point.

a.) indicator b.) equivalence c.) end d.) standardization e.) primary standard 5

10.) A 0.7860 gram sample of impure Na2CO3 is neutralized by 23.48 mL of 0.1082 M HCl. What percentage purity of Na2CO3 was contained in the sample? There are no acidic or basic impurities present in the sample. a.) 34.24% b.) 12.16% c.) 17.13% d.) 32.32 % e.) 68.52%

11.) What is the oxidation number of bromine in KBrO3?

a.) +1 b.) +7 c.) +3 d.) -1 e.) +5

- 12.) What is the oxidation number of P in H2PO4 ion?

a.) -3 b.) +2 c.) +3 d.) +4 e.) +5 6

13.) Balance the following equation in acidic solution. What is the sum of the coefficients?

- 2+ Zn + NO3  Zn + N2 (acidic solution)

a.) 25 b.) 27 c.) 29 d.) 31 e.) 33

14.) Balance the following equation in basic solution. What is the sum of the coefficients?

2- 2- PbO2 + SeO3  PbO + SeO4 (basic solution) a.) 8 b.) 10 c.) 12 d.) 4 e.) 6 7

-2 15.) Chlorous acid HClO2 oxidizes sulfur dioxide SO2 to sulfate ions SO4 and is reduced to chloride ions Cl- in acidic solution. Write the balanced equation for the reaction. What is the sum of the coefficients? a.) 11 b.) 13 c.) 15 d.) 17 e.) 19

2- - - - 16.) In basic solution, CrO4 oxidizes HSnO2 to HSnO3 and is reduced to CrO2 . Write the balanced equation for this reaction. What is the sum of the coefficients? a.) 9 b.) 15 c.) 13 d.) 6 e.) 10 8

17.) Which statement is incorrect?

a.) Energy is the capacity to do work or to transfer heat b.) Kinetic energy is the energy of motion c.) Potential energy is the energy that a system possesses by virtue of its position or composition d.) A process that absorbs energy from its surroundings is called exothermic e.) The Law of Conservation of Energy is another statement of the First Law of Thermodynamics

18.) Given the following standard heats of formation for the following compounds calculate ∆H0 for the following reaction.

CH4 (g) + H2O (g)  CH3OH(l) + H2 (g)

0 ∆H f(kJ/mol) -75 -242 -238 0 a.) +79 kJ b.) -79 kJ c.) +594 kJ d.) -594 kJ e.) -405 kJ

0 19.) Use the data below to calculate ∆H f for benzene, C6H6 (l)

2C6H6 (l) + 15 O2 (g)  12 CO2 (g) + 6 H2O (l) ∆Hrxn = -6535 kJ

∆Hf CO2(g) = -393.5 kJ/mol ∆Hf H2O(l) = -285.8 kJ/mol

a.) 49.1 kJ/mol b.) 3.51x104 kJ/mol c.) 103 kJ/mol d.) 1.76x103 kJ/mol e.) 561 kJ/mol 9

20.) How much heat is absorbed in the complete reaction of 3.00 grams of SiO2 with excess carbon in the reaction below? ∆H0 for the reaction is +624.6 kJ.

SiO2 (g) + 3C (s)  SiC (s) + 2CO (g) a.) 366 kJ b.) 1.13x105 kJ c.) 5.06 kJ d.) 1.33 x104 kJ e.) 31.2 kJ