Mrs. B - 2014 Summer Packet

AP Chemistry Information & Summer Assignment 2014

Introduction

Dear Future AP Chemistry Students

Congratulations on your decision to take Advanced Placement Chemistry! This class has the potential to be one

of the most fun & rewarding classes that you will take in high school. However, please be advised that many

people have found AP Chemistry to be a particularly challenging course with a particularly challenging exam,

even when compared with other AP courses and AP exams.

Remember also that AP classes are taught as college courses—not just college-level courses, but actual college

courses. This means that:

I will do as much as I can to help you learn, but you and you alone are responsible for learning and

understanding everything covered in class.

I will tell you when everything is due, but I won’t chase after you. If you were absent and you need to

turn in an assignment late, you need to remember to show it to me; do not assume I will ask you for it.

If you’re having trouble with something, you need to be proactive about learning it, either by coming in

for help, consulting with your classmates, or by getting outside help. This expectation is effective

immediately, and it applies to this summer assignment. Remember—your job is to succeed; my job is to

help you be successful.

The goal of this summer assignment is to make sure you haven’t completely forgotten Chemistry Honors and to

give you a “warm-up” for AP Chemistry.

The assignment consists of review problems from Chemistry Honors. The problems are due on Wednesday

August 27, 2014. A test on this material will be given on Friday August 29, 2014.

If you have clarification questions on the assignment, you may email me at

Email: Nurgul_K_Balimtas@mcpsmd.org

Warning: don’t leave the assignment until the week before school start!

Sincerely,

AP-Chemistry Teacher

Mrs. Balimtas

Mrs. B - 2014 Summer Packet

First Test

You will be taking your first test in class on Friday, August 29, 2014. The test will consist of questions taken

from an exam intended for students who have completed a first-year high school chemistry course.

Summer Assignment: Honors Chemistry Review Problems

For each problem (and subsequently throughout the year), you must show all of the steps that lead from the

question to your answer, regardless of whether you do the work on paper, on your calculator, or in your head.

(Show as much detail as you would for a mathematical proof.)

Students should review chapters 1-5 of your AP textbook. Please see me if you wish to check out a

textbook. Please do not hesitate to stop by the AP chemistry room, B-217 , if you have any questions or

need any additional materials to help in your preparation. Enjoy your summer!

1. MATH SKILLS BCC-H AP-CHEMISTRY

These problems are intended to REFRESH the skills you already have, please work on them. Questions SIGNIFICANT FIGURES: Perform the following calculations and express the answer with the appropriate number of significant figures, and the correct units. 1. 136.24 cm + 12.6 cm 25.42 cm 5. (16.2 m/s2) x (273.4 s)

2. (9.62x104 kg/m3) x (78 m3) 6. (856 g + 97 g) x (0.043 mL/g)

3. mL003746.0

)mg162.0()mg0321.0( 7.

)kg10643.1(

)000.2)(36.5(

22

s

mkg2

2

4. )K26)(mol100.0(

)mL1047.3)(kPa10234.6( 96

8. mol1089.1

)mol1047.1()mol1033.2(3

33

LOGARITHMS: Evaluate “x” to the correct number of significant figures.

Note, the significant figure rules are the same for base 10 logs and natural logs :

log(18.6) = 1.270 102.33 = 0.0047

3 SF 3 dp 2 dp 2 SF

9. x = log(0.0021) 13. x = e13.6 17. ln

4.27

x= 0.038

10. x = 105.42 14. 9.44 = log(x)

11. log(x) = 6.2 15. ln(x) = 57.21 18. log

x

0156.0 = 0.00766

12. x = ln(3.396x104) 16. x = log(41.1)

Mrs. B - 2014 Summer Packet

ALGEBRA: Evaluate “x” (assume that whole numbers are exact here). When using the quadratic equation to find x, use the SF in A, B, and C to determine the SF for the answers.

19. 9

x4 = 16 23. (2x)2 (4x)3 = 2.6x10

5 27. (x + 0.12)(x 1.33) = 4.60

20. x2.3

42.6 = 9.917 24. (0.13x)2 (7.246) = (5.7x)4 28. x3 + 9 = 73

21. 0.55x2 = 1.34 25. x046.0

x2

= 7.210

4 29. (2x 4)(x 6) = 48

22. 8x3 = 216 26. 2

2

)x320.0(

x0000.4

= 1.6010

3 30. 2)3x(

x

=

x

60.2

2. CONVERSIONS, FACTOR-LABEL METHOD, AND DENSITY (Ch. 1) BCC-H AP-CHEMISTRY Questions 1. Convert 172 inches to millimeters.

2. Convert 6.21013 nanometers to miles.

3. Convert 68.2 F to Celsius.

4. Convert 443.62 F to Kelvin.

5. Convert 12.94 C to Fahrenheit.

6. Convert 976 K to Celsius.

7. Convert 25.66 K to Fahrenheit.

8. Convert 397.6 C to Kelvin.

9. Convert 3.00108 meters per second to miles per hour.

10. Convert 37.64 pounds per cubic foot to grams per liter.

11. What is the density of lead sulfide if a sample has a mass of 12.4 g and a volume of 1.64 cm3 ?

12. What is the density of a particular type of plastic if a solid block of it measures 15.5 cm 4.60 cm 1.78 cm and has a mass of 98 g?

13. The density of gasoline is 0.70 g/mL. What is the mass of a tankful of gasoline if the tank holds 12.0 gallons?

14. The density of bromine is 3.12 g/mL. How many liters are needed to give 1.25 pounds of bromine?

15. What is the mass of 176 cubic inches of iodine (density = 4.93 g/mL)?

16. The diameter of a chlorine atom is 200 pm. How many chlorine atoms lined up end to end would form a line 1.0 inch long?

Mrs. B - 2014 Summer Packet

3. WRITING FORMULAS AND NAMING COMPOUNDS (Ch. 2 ) BCC-H AP-CHEMISTRY Questions Name these ionic and molecular compounds: 1. NaBr 10. Al2Se3 19. Na2S2O3

2. CaO 11. Cs3N 20. CuO

3. MnPO4 12. CrS 21. N2O

4. P4O10 13. BBr3 22. Cr(H2PO4)3

5. Ba(OH)2 14. NH4OH 23. PbSO3

6. (NH4)2SO4 15. Ca3(PO4)2 24. B2O3

7. BrF5 16. N2O5 25. (NH4)2CO3

8. Cu2O 17. CdI2 26. BaH2

9. Zn(CN)2 18. Al2Te3 27. Hg2Cl2

Write the formulas for these ionic and molecular compounds: 28. barium chloride 37. silver chromate 46. strontium chlorate

29. potassium sulfide 38. potassium permanganate 47. mercury(II) bromide

30. iron(II) hypochlorite 39. ammonium oxalate 48. iron(III) nitrate

31. silicon tetrachloride 40. chlorine dioxide 49. tin(IV) iodide

32. rubidium carbide 41. lithium chlorite 50. cesium dichromate

33. ammonium phosphide 42. tetraarsenic hexoxide 51. gold(III) bisulfite

34. krypton difluoride 43. sodium sulfate 52. strontium carbonate

35. calcium nitrate 44. lead(II) bicarbonate 53. bismuth chlorite

36. magnesium sulfite 45. nickel thiocyanate 54. aluminum monohydrogen phosphate

Write the names or formulas for these acids: 55. HNO3 64. HNO2 73. hydrophosphoric acid

56. HCl(aq) 65. H2S2O3 74. thiocyanic acid

57. H2Cr2O7 66. H3N(aq) 75. chlorous acid

58. H2SO3 67. HF(aq) 76. hydrobromic acid

59. HI(aq) 68. perchloric acid 77. carbonic acid

60. H2C2O4 69. hydrocyanic acid 78. hydroarsenic acid

61. HMnO4 70. phosphoric acid 79. chloric acid

62. H2Se(aq) 71. hypochlorous acid 80. hydrosulfuric acid

63. H2CrO4 72. sulfuric acid 81. acetic acid

Mrs. B - 2014 Summer Packet

4. ACIDS AND BASES II pH, pOH, Dissociation Constants, Conjugate Acids and Bases AP-CHEMISTRY

Data:

Acids Bases

Name Formula Ka1 Ka2 Ka3 Name Formula Kb

acetic acid HC2H3O2 1.8×105 x x ammonia NH3 1.8×10

5

ascorbic acid H2C6H6O6 6.8×105 2.7×10

12 x aniline C6H5NH2 4.1×1010

benzoic acid HC7H5O2 6.3×105 x x butylamine C4H9NH2 5.9×10

4

carbonic acid H2CO3 4.3×107 4.7×10

11 x dimethylamine (CH3)2NH 9.6×104

citric acid H3C6H5O7 7.1×104 1.7×10

5 6.3×106 ethylamine C2H5NH2 4.3×10

4

cyanic acid HCNO 3.5×104 x x hydroxylamine NH2OH 6.6×10

9

hydrocyanic acid HCN 6.2×1010 x x methylamine CH3NH2 4.4×10

4

hydrofluoric acid HF 6.8×104 x x pyridine C5H5N 1.5×10

9

hypochlorous acid HOCl 3.0×108 x x trimethylamine (CH3)3N 7.4×10

5

hypobromous acid HOBr 2.1×109 x x

hypoiodous acid HOI 2.3×1011 x x

lactic acid HC3H5O3 1.4×104 x x

oxalic acid H2C2O4 5.6×102 5.4×10

5 x

phosphoric acid H3PO4 7.1×103 6.3×10

8 4.5×1013

sulfurous acid H2SO3 1.2×102 6.6×10

8 x

Questions

1. What is the pH of a 0.0459 M HBr solution?

2. What is the pH of a solution with a pOH of 9.67?

3. What is the pH of a 0.024 M Ba(OH)2 solution?

4. What concentration of HCl gives a pH of 1.23?

5. How many grams of HNO3 do you need in 500.0 mL of solution to make the pH = 2.57?

6. What concentration of NaOH gives a pH of 10.92?

7. What concentration of Sr(OH)2 gives a pOH of 4.32?

8. What concentration of HClO4 gives a pOH of 12.34?

9. How many grams of KOH are needed to give a pH of 11.98 in 4.00 L of solution?

Mrs. B - 2014 Summer Packet

Write the formula and give the name for the conjugate acid of each of these bases.

10. methylamine, CH3NH2 13. fluoride, F1 16. trimethylamine, (CH3)3N

11. butylamine, C4H9NH2 14. hydroxide, OH1 17. water, H2O

12. carbonate, CO32 15. hydrogen phosphate, HPO4

2

Write the formula and give the name for the conjugate base of each of these acids.

18. cyanic acid, HCNO 21. hydronium, H3O1+ 24. water, H2O

19. arsenic acid, H3AsO4 22. hydrogen phosphate, HPO42 25. dimethylammonium, (CH3)2NH2

1+

20. ethylammonium, C2H5NH31+ 23. benzoic acid, HC7H5O2

Refer to the Data given on the first page to determine the indicated dissociation constant for each of the following.

26. Ka for H2C6H5O71 29. Kb for CNO1 32. Ka for C5H5NH1+

27. Kb for H2C6H5O71 30. Ka for HSO3

1 33. Kb for CO32

28. Ka for C6H5NH31+ 31. Kb for C2O4

2

5. WRITING AND BALANCING CHEMICAL EQUATIONS (Ch. 2) AP-CHEMISTRY Questions Balance the following equations: 1. Fe(s) + H2O(g) Fe3O4 (s) + H2 (g)

2. Si(s) + NaOH(aq) + H2O(l) Na2SiO3 (s) + H2 (g)

3. Fe2O3 (s) + H2 (g) Fe(s) + H2O(l)

4. As2S3 (s) + O2 (g) As4O6 (s) + SO2 (g)

5. Ca3P2 (s) + H2O(l) PH3 (g) + Ca(OH)2 (aq)

6. B2O3 (s) + CaF2 (aq) + H2SO4 (aq) BF3 (g) + CaSO4 (s) + H2O(l)

7. Pb(NO3)2 (s) PbO(s) + NO2 (g) + O2 (g)

8. Mg3N2 (s) + H2O(l) NH3 (aq) + Mg(OH)2 (s)

9. PCl5 (s) + H2O(l) HCl(aq) + H3PO4 (aq)

10. H2CrO4 (aq) + KOH (aq) H2O(l) + K2CrO4 (aq)

Mrs. B - 2014 Summer Packet

Write complete balanced equations for the following reactions.

Note: complete combustion of a carbon compound means that the compound burns in the presence of oxygen to produce carbon dioxide and water. 11. complete combustion of liquid 1-pentanol, C5H11OH

12. decomposition of solid copper(II) nitrate into solid copper(II) oxide, nitrogen dioxide gas and oxygen

13. formation of solid ammonium dichromate from its elements

14. reaction between aqueous gold(III) iodide and hydrogen to produce aqueous hydroiodic acid and solid gold

15. reaction between aqueous barium hydroxide and aqueous perchloric acid to produce aqueous barium perchlorate and water

16. complete combustion of liquid benzene, C6H6

17. decomposition of solid silver oxide into its elements

18. formation of liquid dinitrogen pentoxide from its elements

19. reaction between solid lead and aqueous silver nitrate

20. reaction between solid sodium bicarbonate and aqueous phosphoric acid

21. complete combustion of liquid heptane, C7H16

23. formation of solid magnesium nitride from its elements

24. reaction between aqueous tin(II) acetate and solid chromium

25. reaction between aqueous lithium phosphate and aqueous nickel cyanide to produce

26. Solid copper + magnesium sulfate

27. C5H12(l) + O2(g)

29. Ammonium chloride + silver nitrate

30. Fe2O3(s)

31. For each of the reactions in #11-30, specify whether it is combustion, synthesis, decomposition, single replacement,

or double replacement, precipitation

6. ATOMS, MOLECULES, MOLES, AND GRAMS (Ch. 3) AP -CHEMISTRY

Questions 1. What is the atomic mass of copper, Cu ?

2. How many grams are there in 36.34 moles of Cu ?

3. How many moles are there in 3.7105 grams of Cu ?

4. How many copper atoms are there in 92.56 moles of Cu ?

5. How many copper atoms are there in 0.104 grams of Cu ?

6. What is the molar mass of bromine pentafluoride, BrF5 ?

7. How many grams are there in 0.04651 moles of BrF5 ?

Mrs. B - 2014 Summer Packet

8. How many moles are there in 89.443 grams of BrF5 ?

9. How many fluorine atoms are there in 13 BrF5 molecules ?

10. How many total atoms are there in 13 BrF5 molecules ?

11. How many BrF5 molecules are there in 9.164 moles of BrF5 ?

12. How many fluorine atoms are there in 4.4106 moles of BrF5 ?

13. How many BrF5 molecules are there in 435 grams of BrF5 ?

14. How many fluorine atoms are there in 0.0064 grams of BrF5 ?

15. What is the molar mass of ammonium chromate, (NH4)2CrO4 ?

16. How many milligrams are there in 0.164 moles of (NH4)2CrO4 ?

17. How many kilomoles are there in 19 kilograms of (NH4)2CrO4 ?

18. How many nitrogen atoms are there in 37 (NH4)2CrO4 formula units ?

19. How many ammonium ions are there in 2.936 moles of (NH4)2CrO4 ?

20. How many (NH4)2CrO4 formula units are there in 7.67107 grams of (NH4)2CrO4 ?

21. How many oxygen atoms are there in 8.3 grams of (NH4)2CrO4 ?

22. What is the molar mass of perchloric acid, HClO4 ?

23. How many pounds are there in 641 moles of HClO4 ?

24. How many millimoles are there in 8.8103 grams of HClO4 ?

25. How many chlorine atoms are there in 173 HClO4 molecules ?

26. How many calcium atoms are there in 9.5 moles of Ca3(PO4)2 ?

27. How many Ca3(PO4)2 formula units are there in 0.000410 gram of Ca3(PO4)2 ?

28. How many phosphate ions are there in 9832 grams of Ca3(PO4)2 ?

7. % COMPOSITION, EMPIRICAL AND MOLECULAR FORMULAS (Ch. 3) AP-CHEMISTRY

Questions

Calculate the percent composition by mass of the following:

1. C4H6O2 4. Na3PO4

2. C3H3N 5. (CH3)2N2O

3. YBa2Cu3O7

Answer these questions:

6. Cyanocobalamin (vitamin B12 ) contains 4.34% cobalt by mass. What is the molar mass of cyanocobalamin,

assuming that there is one atom of cobalt in every molecule ?

Mrs. B - 2014 Summer Packet

7. Hemoglobin is 0.342% Fe by mass, and each hemoglobin molecule contains four iron atoms. What is the molar mass of hemoglobin ?

8. An ionic compound formed from aluminum and a group VIA element is 18.56% Al by mass. What is the formula of the compound ?

9. A gold compound decomposes upon heating with a catalyst to gold(III) chloride and oxygen gas. If a 0.07976 g sample is completely decomposed and produces 30.92 mg of oxygen gas, then what is the percent oxygen in the gold compound ?

Find the empirical formulas for the following:

10. a compound that is 34.59% Na, 23.31% P, and 42.10% O by mass

11. a compound, a sample of which contains 0.388 g Li, 2.922 g Cr, and 3.147 g O

12. a compound, a sample of which contains 15.4 g Al, 27.5 g S, and 54.8 g O

13. a compound that is 24.5% Na, 14.9% Si, and 60.6% F by mass

Find the empirical and molecular formulas for the following:

14. a compound composed of only antimony and oxygen which is 83.53% Sb by mass and has a molar mass between 550 and 600 g/mol

15. a compound that is 14.5% C, 1.8% H, 64.3% Cl, and 19.4% O by mass, with a molar mass of 662 g/mol

16. a compound, a sample of which contains 0.398 moles of the substance, and consists of 38.2 g C, 4.8 g H, and 38.2 g O

17. a compound that is 80% I and 20% O by mass, with a molar mass of 318 g/mol

8. STOICHIOMETRY AND LIMITING REACTANTS I Grams (Ch. 3) AP-CHEMISTRY

Questions

I. Propane, when used as a fuel, reacts with oxygen to produce carbon dioxide and water:

___ C3H8(g) + ___ O2(g) ___ CO2(g) + ___ H2O(l)

1. Balance the equation.

2. What mass of oxygen will be required to react exactly with 96.1 grams of propane?

3. What mass of carbon dioxide is produced when 96.1 grams of propane react with oxygen?

4. Calculate the mass of water formed by 96.1 grams of propane.

II. Solid lithium hydroxide is used in space vehicles to remove exhaled carbon dioxide. The products are

solid lithium carbonate and liquid water.

5. Write the balanced chemical equation for this reaction.

6. Calculate the mass of carbon dioxide absorbed by 1.00 kg of lithium hydroxide.

10

III. Aluminum can be oxidized by hydrochloric acid: ___ Al(s) + ___ HCl(aq) ___ AlCl3(aq) + ___ H2(g)

7. Balance the equation.

8. What mass of metal is needed to produce 1.00 gram of hydrogen?

IV. Methane reacts with steam to produce hydrogen gas and carbon monoxide:

___ CH4(g) + ___ H2O(g) ___ H2(g) + ___ CO(g)

9. Balance the equation.

10. How much hydrogen gas is produced when 249 g of methane reacts with 249 g of steam?

11. Which reactant is limiting and which is in excess?

12. How much of the excess reactant will be left over?

V. Ammonia can be produced by the Haber process: ___ N2(g) + ___ H2(g) ___ NH3(g)

13. Balance the equation.

14. When 25.0 kg of nitrogen and 5.00 kg of hydrogen are mixed, what is the theoretical yield of ammonia, in kg?

15. How much of each reactant is left over?

16. What is the percent yield of ammonia if 21.3 kg are actually produced?

9. MOLARITY AND DILUTION (CHP-4) AP- CHEMISTRY

Questions

Note: Assume that liquid volumes are additive.

1. What is the molarity of the solution which contains 0.00234 moles of solute in 175 mL of solution?

2. How many moles of solute are there in 692.10 mL of a 4.2513 M solution?

3. What is the molarity of chromic acid in the solution which contains 3.77 grams of H2CrO4 in 675 mL of

solution?

4. What volume of 9.26 M NaOH solution is needed to give 0.5166 moles of sodium hydroxide?

5. What volume of 6.00 M HBrO4 solution is needed to give 11.4 grams of perbromic acid?

6. What is the molarity of a solution if 3.50 L contains 28 grams of potassium carbonate?

7. How many moles of hydroxide ions are there in 82.35 mL of a 2.164 M Sr(OH)2 solution?

8. What is the molarity of chloride ions in a solution prepared by dissolving 168.5 mg of CaCl2 in 975.0 mL of

water? (Assume no volume change upon addition of the solid.)

9. What is the total molarity of nitrate ions in 3.500 L of a solution which is 0.7500 M in aluminum nitrate and 0.1250 M in sodium nitrate?

11

10. You must prepare a 0.540 M solution of potassium permanganate. You have 27.5 grams of solid KMnO4.

What is the maximum volume of solution that you can prepare?

11. A solution is 0.04623 M in K3PO4. If 30.00 mL of this solution is added to enough water to make 125.00 mL

total, then what is the concentration of this new diluted solution?

12. If enough water is added to 28.43 mL of a 12.63 M Ca(NO3)2 solution to make 150.0 mL of solution, then what

is the final concentration of calcium nitrate?

13. What molarity of potassium permanganate solution is needed if 10.0 L of it mixed with 7.5 L of water gives a 4.50 M KMnO4 solution?

14. What is the final volume if 43.52 mL of 0.234 M sulfuric acid is mixed with enough water to make a 0.0345 M solution?

10. LEWIS STRUCTURES, GEOMETRY, AND POLARITY OF MOLECULES (Ch.9)

Questions

A. Draw the Lewis structures for the following, including all equivalent resonance structures, if appropriate.

1. CCl3F 4. C2H4 7. BCl3 10. PO21

2. H3O1+ 5. SO3 8. CO2 11. CH2O

3. CH3OH 6. H2CO3 9. PBr3 12. C2O42

B. Indicate the molecular geometry, the bond angle, and the hybridization of the orbitals for EVERY

central atom for the molecules and ions in Part A.

C. Indicate whether the molecules in Part A are polar or nonpolar. For the ions, simply write N/A.

D. How many sigma bonds and how many pi bonds are there in the molecules and ions in Part A?

11. INTERPARTICLE FORCES (Ch. 11) BCC- H

Questions AP –Chemistry

Identify the major interparticle forces present in the following:

1. PBr3 4. NH3 7. Cu

2. Ca 5. SiO2 8. K3PO4

3. Ne 6. Cl2 9. SO3

Which member of each pair of solids should have the higher melting point ? Briefly explain why.

10. PF3 or AlF3 11. Na or Al 12. PCl3 or SCl2

Which member of each pair should be more volatile at a given temperature ? Briefly explain why.

13. I2 or NaI 14. CCl4 or CI4 15. NaCl or KBr

12

12. GAS LAWS, GAS DENSITIES, AND PARTIAL PRESSURES (Ch. 10) AP- CHEMISTRY

Questions

1. What temperature (C) is needed for 5.625 g of oxygen to exert a pressure of 1.20 bar in a 3.00 L container?

2. If 48.69 millimoles of nitrogen occupy 1.72 cubic feet at 53.6 F, what is the pressure?

3. What volume would an ideal gas occupy if 6.642103 mol exerts a pressure of 85.72 millibars at 16.91 C?

4. How many helium atoms are needed to exert a pressure of 15.0 atm in a 100.0 mL container at 25.0 C?

5. The volume is held constant as a sample of nitrogen is heated from 22.67 C to 69.35 C. If the initial pressure was 105.6 kPa, what will the final pressure be?

6. If 0.357 mol of carbon monoxide has a pressure of 1.44 atm, what pressure will 12.88 g of carbon monoxide have at the same volume and temperature?

7. If the pressure of a gas sample is 56.1 psi in a 4.00 L container at 34 °C, then what will the pressure be if the volume is changed to 7.00 L and the temperature is changed to 2 °C?

8. What is the molar mass of the gas which has a density of 2.523103 g/mL at 37.35 C and 1.086 atm?

9. What are the partial pressures and the total pressure in a gas mixture containing 4.00 g oxygen, 3.00 g methane, and 14.00 g chlorine in a 500.0 mL container at 20.44 C? (Assume no chemical reactions occur.)

10. A mixture of gases contains 15.0 grams each of ammonia, nitrogen, and carbon monoxide. If the total pressure of the mixture is 145.6 kPa, what is the partial pressure of each component? (Assume no chemical reactions occur.)

11. A mixture of gases contains 1.578 grams of methane and some amount of carbon dioxide. If the total pressure is 972.41 mm Hg, the volume is 10.00 L, and the temperature is 31.0 C, how many grams of carbon dioxide are there? (Assume no chemical reactions occur.)

13. SPECIFIC HEAT, CALORIMETRY, AND ENTHALPY CHANGES (Ch. 5)

Questions

Use the following data to answer the first 6 questions:

Specific Heats (J/gC)

Al2O3 (s) 0.775 Cu(s) 0.387 Hg(l) 0.14

C2H5OH(l) 2.45 H2O(l) 4.184 Pyrex glass 0.78

1. A 1.62 gram sample of sodium chloride absorbs 27.78 J as it is heated from 16.4 C to 36.2 C. What is the

specific heat of sodium chloride ?

2. If 3.50 grams of liquid mercury absorbs 1.97 calories, by how much will its temperature change ?

3. A 497 milligram sample of aluminum oxide is initially at 25.0 C. If it absorbs 16.11 J of heat, then what will its final temperature be ?

13

4. A 1.00 pound sample of an unknown substance is heated from 12.66 C to 98.71 C by applying 15.0 kJ of energy. Which substance listed in the table is this ?

5. How much energy is needed to heat 100.0 grams of Pyrex glass from 0.0 C to 100.0 C?

6. If 50.0 grams of copper initially at 145.0 C is put into 150.0 mL of water initially at 25.00 C, then what will the final temperature of the mixture be ? Hint: assume that all of the heat lost by the hot copper is absorbed by the cold water.

In the following questions, assume the mixture in the coffee cup has the same density and specific heat as pure water.

7. A coffee-cup calorimeter initially contains 125.0 grams of water at 24.20 C. Potassium bromide (10.5 grams), also at 24.20 C, is added to the water. After all of the potassium bromide dissolves, the final temperature is 21.10 C. Calculate H for this reaction:

KBr(s) water

K1+(aq) + Br1(aq)

8. In a coffee-cup calorimeter, 100.0 mL of 9.00 M HCN and 100.0 mL of 4.50 M Ba(OH)2 are mixed. Both

solutions were originally at 24.6 C. The maximum temperature observed during the experiment is 35.2 C. Calculate the enthalpy change for the neutralization reaction that occurs.

9. A 5.00 gram chunk of potassium is dropped into 1.000 kg of water initially at 24.00 C in a coffee-cup calorimeter. The temperature at the end of the reaction is 30.00 C. Find H for the reaction which occurs, assuming the pressure remains constant:

2 K(s) + 2 H2O(l) 2 KOH(aq) + H2 (g)

For the next 4 questions, refer to the following thermochemical equation: 4 NH3 (g) + 5 O2 (g) 4 NO(g) + 6 H2O(g) H = 906 kJ

10. How many moles of ammonia must react to produce 1234 kJ ?

11. How much heat is released when 62.4 grams of steam are produced ?

12. How many oxygen molecules must react to produce 1.00 calorie ?

13. If 88 grams of nitrogen monoxide are produced, how much heat is released ?

Calculate H for the following reactions using this data:

Standard Heats of Formation (kJ/mol)

Ag(s) 0 Cr2O3 (s) 1141 H2S(g) 20.6

Ag2O(s) 31.1 Fe(s) 0 O2 (g) 0

C6H12O6 (s) 1273.3 Fe2O3 (s) 822.2 PbO(s) 219.2

CO(g) 110.5 H2 (g) 0 PbS(s) 100.0

CO2 (g) 393.5 H2O(g) 241.8 SO2 (g) 296.9

Cr(s) 0 H2O(l) 285.9

14. 2 H2S(g) + 3 O2 (g) 2 H2O(l) + 2 SO2 (g)

14

15. 2 PbS(s) + 3 O2 (g) 2 SO2 (g) + 2 PbO(s)

16. Fe2O3 (s) + 3 CO(g) 2 Fe(s) + 3 CO2 (g)

17. C6H12O6 (s) + 6 O2 (g) 6 H2O(l) + 6 CO2 (g)

Use Hess’s Law to find the enthalpy changes for the following reactions:

18. reaction: NH3 (g) + CH4 (g) HCN(g) + 3 H2 (g)

data: N2 (g) + 3 H2 (g) 2 NH3 (g) H = 92.2 kJ

C(s) + 2 H2 (g) CH4 (g) H = 74.7 kJ

2 C(s) + H2 (g) + N2 (g) 2 HCN(g) H = +270.3 kJ

19. reaction: 2 N2 (g) + 5 O2 (g) 2 N2O5 (g)

data: H2 (g) + ½ O2 (g) H2O(l) H = 285.9 kJ

N2 O5 (g) + H2O(l) 2 HNO3 (l) H = 76.6 kJ

N2 (g) + 3 O2 (g) + H2 (g) 2 HNO3 (l) H = 348.2 kJ

20. reaction: KClO3 (s) + 3 PCl3 (g) 3 POCl3 (g) + KCl(s)

data: 2 KCl(s) + 3 O2 (g) 2 KClO3 (s) H = +78.0 kJ

P4 (s) + 6 Cl2 (g) 4 PCl3 (g) H = 1148.0 kJ

P4 (s) + 2 O2 (g) + 6 Cl2 (g) 4 POCl3 (g) H = 2168.8 kJ