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2015-16 GenChem Final ReviewPart I: MULTIPLE CHOICE QUESTIONS: 70% of Final

UNIT 7: 9.1 – 9.4 Stoichiometry

Consider the following equation for questions 1 thru 3

2C2H2 (g)+ 5O2 (g) → 4CO2 (g) + 2H2O(g) acetylene

1) If 0.500 mol of acetylene is allowed to completely react with oxygen, what is the final yield of CO2 in moles?

A) 2.00 mol B) 4.00 mol C) 1.00 mole D) 0.100 mole E) 0.500 mole

2) If 20.0 g of acetylene is allowed to completely react with oxygen, how many grams of O2 are reacted?

A) 9.85 g B) 24.6 g C) 5.00 g D) 61.4 g E) 20.0 g

3) If 40.0 g of acetylene is allowed to react with 40.0 g of oxygen , how many grams of CO2 are formed?

A) 135 g B) 44.0 g C) 40.0 g D) 80.0 g E) 55.0 g

4) When 50.0 g of acetylene is allowed to react with excess oxygen, 75.0 g of CO2 are formed. What is the percent yield of carbon dioxide?

A) 100 % B) 150 % C) 6.7 % D) 44.4 % E) 88.8 %

5)

Magnesium sulfate reacts with barium chloride according to the following balanced equation. If 1.20 g of magnesium sulfate is allowed to react with 1.00 g of barium chloride in a water solution, what is the limiting reagent?

MgSO4(aq) + BaCl2(aq) → BaSO4(s) + MgCl2(aq)

A) magnesium chlorideB) barium chlorideC) magnesium sulfateD) marium sulfateE) water

UNIT 8: 3.3-3.5, 10.5 Thermochemistry

6) A solid is dissolved in a coffee cup calorimeter. Which of the following observations suggests that the process is exothermic?

A) temperature of the solution decreasesB) temperature of the solution increasesC) temperature of the solution stays the same

7) The specific heat of a substance is defined as ___.A) the energy required to raise the temperature of 1 gram of the substance by 1oCB) the energy required to vaporize 1 mole of the substance at its normal boiling pointC) the average kinetic energy of the substanceD) the energy required to raise the temperature of the entire substance by 1o

E ) the hotness or coldness of the substance

8) The graph below represents the uniform heating of a solid, starting below its melting point.

What portion of the graph shows the warming of the liquid phase of the substance?A) EF B) ABC) DE D) CD E) BC

9) What is the name of the process which occurs when a substance passes from the gas to the liquid phase?

A) sublimation B) condensation C) melting D) freezing E) deposition

The following table lists the specific heats for a few substances. Use this table to answer Question 10 and 11

SubstanceSpecific Heat

( )Copper (Cu) 0.385Iron (Fe) 0.452Silver (Ag) 0.235

Sodium chloride (NaCl)(s) 0.864Ammonia (NH3)(g) 2.04

10) If the same amount of heat is supplied to 10.0 g of each substance all at 21.0oC, which substance would

experience the LARGEST change in temperature?A) Cu B) Fe C) Ag D) NaCl E) NH3

11) A 25.0 g piece of copper undergoes a temperature increase of 100.0oC. How much energy,

in joules, did the copper absorb ?A) 962 J B) 2500 J C) 6490 J D) 9.63 J E) 0.0962 J

12) A solute is dissolved in water in a coffee cup calorimeter and the dissolving process results in a positive ΔHSol'n. The temperature of the resulting solution will:

A) increase B) decrease C) stay the same

UNIT 9: Chp. 11.1-11.8, 11.10 Gas Laws

13)

The “initial volume” balloon is at atmospheric pressure. Which balloon(s) shown above represent the balloon after it has been put into a chamber with a lower pressure.

A)

Balloon A B ) Balloon B C) Balloon C D) Balloons B and C E) Balloons A and B

14)

Charles’s Law states that the volume of a gas _____ when the _____ decreases. A)

increases, quantity of gas B)

decreases, temperature C)

decreases, pressure D)

increases, pressure E)

increases, temperature

15)

What unit of temperature is used in gas law calculations? A)

Kelvin B)

Celsius C)

Fahrenheit D)

either Celsius or Fahrenheit E)

either Celsius or Kelvin

16)

1 atmosphere of pressure is the same as ___ mmHg.A)

1 B) 600 C) 200 D) 100 E) 760

17)

According to the kinetic molecular, KMT, theory of gases, particles of a gas A)

are very large B)

lose their valence electrons. C)

decrease in kinetic energy as temperature increases. D)

are very far apart. E)

move slowly.

18)

According to Avogadro's law, the volume of a gas A)

depends only on the number of moles in the sample. B)

is directly related to the number of moles at constant temperature and pressure. C)

is inversely related to the number of moles at standard temperature and pressure. D)

is inversely related to the number of moles at constant temperature and pressure. E)

depends only on the temperature and pressure.

19)

At STP, temperature and pressure have the values of A)

0 K and 1 atm. B)

760 K and 273 atm. C)

0 K and 760 mmHg. D)

273 K and 1 mmHg. E)

273 K and 760 mmHg.

20) The mathematical expression of the ideal gas law is ________.

A) P1

T1 =

P2

T2 B) PV = nRT C) P1V1 = P2V2 D) PT = P1 + P2 + P3…. E)

V 1

P1 =

V 2

P2 21)

At STP, what is the volume of 1.0 mol of carbon dioxide? A)

1.00 L B) 12.2 L C) 273 L D) 22.4 L E) 44.0 L

22)

The pressure of 5.00 L of gas increases from 1.50 atm to 1.63 atm. What is the final volume of the gas, assuming constant temperature?

A)

5.00 L B) 4120 L C) 0.00600 L D) 4.60 L E) 5.40 L

23)

A 10.0 liter balloon was taken from a temperature of 298 K and placed in a freezer at a temperature of 258 K. What was the new volume if pressure is constant?

A)

8.66 liters B) 115 liters C) 2.50 liters D) 250. liters E) 11.60 L

24)

A gas contained in a steel tank has a pressure of 1.5 atm at a temperature of 320 K. What will be the gas pressure when the temperature changes to 450 K?

A)

2.1 atm B) 1.1 atm C) 0.47 atm D) 0.47 atm E) 0.94 atm

25)

At 570. mmHg and 298 K a gas sample has a volume of 2270 mL. What is the final pressure (in mmHg) at a volume of 1250 mL and a temperature of 448 K?

A)

7000 mmHg B) 690 mmHg C) 470 mmHg D) 210 mmHg E) 1560 mmHg

26)

The total pressure in a mixture of gases is equal to the partial pressure(s) of A)

the gas with the greatest number of moles. B)

all the gases added together. C)

the gas that occupies the largest volume. D)

the gas with the smallest number of moles. E)

the gas with the highest molecular weight.

27)

A cyclopropane-oxygen mixture is used as an anesthetic. If the partial pressure of cyclopropane in the mixture is 334 mmHg and the partial pressure of the oxygen is 1.02 atm, what is the total pressure of the mixture in torr?

A)

335 torr B) 432 torr C) 1.44 torr D) 1110 torr E) 760 torr

28)

A 0.315 mol sample of He gas has a pressure of 0.123 atm at 428 Kelvin. What is the volume of the sample?

A)

573 K B) 546 L C) 1.35 L D) 118 L E) 90.0 L

UNIT 10 : Chp. 9.5, 13.1-13.2, 13.5 Kinetics

For Questions 29-31, match the following to the energy diagram shown above.

29) activation energy, Ea 30) ΔHRXN 31) this reactions is A) A A) A A) exothermic

B) B B) B B) endothermicC) C C) C

Answer Questions 32-35 based on the equilibrium equation shown below.

CO2 (g) + H2(g) CO (g) + H2O(l) ΔHRXN = ─ 2.8 kJIn which direction will the equilibrium shift in response to each change listed below:

A)

towards productsB)

towards reactantsC)

no change

36) The following chemical equation represents what happens when solid NaOH heated.

NaOH(s) + HEAT → NaOH(l) Which of the following phrases best describes this process?

A) endothermic, heat is absorbed by the systemB) exothermic, heat is absorbed by the systemC) endothermic, heat is released by the systemD) exothermic, heat is released by the systemE) endothermic, heat is released by the surroundings

UNIT 11: 12.5 Solutions/ Dilutions

37) What volume of a 3.5 M stock solution is necessary to make 100. mL of a 0.1 M dilution?A) 2.9 mL B) 35 mL C) 350 mL D) 0.35 mL E) 10. ml

38)

Change Direction of Shift

32) decrease temperature A) or B) or C)33) decrease volume A) or B) or C)34) add CO(g) A) or B) or C)35) remove some H2O(l) A) or B) or C)

What is the molarity of a solution which contains 58.4 g of sodium chloride dissolved in 500 mL of solution?

A)

1.50 M B) 1.00 M C) 2.00 M D) 0.500 M E) 4.00 M

39)

How many moles of CaCl2 are in 150. mL of a 2.00 M of CaCl2 solution? A)

300. mol B) 0.300 mol C) 0.0133 mol D) 13.3 mol E) 13.3 mol

40)

How many milliliters of 2.25 M KOH solution are needed to provide 0.660 mol of KOH? A)

0.293 mL B) 2.93 mL C) 293 mL D) 29.3 mL E) 34.1 mL

41)

How many moles of CaCl2 are in 250. mL of a 3.00 M of CaCl2 solution? A) 1.33 mol B) 0.750 mol C) 83.3 mol D) 750. mol E) 3.00 mole

42) What is the molarity of 500.0 mL of a dilution made with 50.0 mL of a 2.50 M stock solution? A) 125 M B) 1 × 104 M C) 10 M D) 20 M E) 0.25 M

UNIT 12: Chp. 14.1,14.3, 14.5-14.8 Acids and Bases

43)

The indicator phenolphthalein is ___ in acid and ___ in base.A) colorless, pink B) pink, blue C) blue, pink D) pink, colorless E) light blue, dark blue

44)

What type of reaction is shown by the chemical equation below?

HCl(aq) + NaOH(aq) → H2O(l) + NaCl (aq)

A)

single replacement B) synthesis C) neutralization D) combustion E) decomposition

45)

What is the [OH - ] in a solution with [H3O+] = 1.0 × 10 − 10 M? A)

1.0 × 10− 7 M B) 1.0 × 10− 3 M C) 1.0 × 102 M D) 1.0 × 10− 4 M E) 1.0 × 10− 18 M 46)

Which of the following is incorrectly identified? A)

Ba(OH)2, strong base B) HF, strong acid C) NH3, weak base D) HCl, strong acid

47)

Calculate the acid concentration of a sample of acid rain with a pH of 8.11. A)

4.2 × 10-1 M B) 1.0 × 10-4 M C) 0.62 M D) 6.3 × 10-5 M E) 7.7 × 10-9 M

48)

What is the pOH of a solution with a pH of 11.5? A)

2.5 B) 0.115 C) 14.0 D) 0.25 E) 10.3

49)

What is the pH of a solution with [H3O+ ] = 1.0 × 10− 5 M? A)

9.0 B) 5.0 C) -9.0 D) -5.0 E) 1.0 × 10− 5 50) Which of the following is true in a acidic solution?

A) [H+] = [OH−] B) [H+] > [OH−] C) [H+] < [OH−] D) [H+] = 0 E) [OH−] = 0

51) A solution with a pH of 8.0 is ___ times more basic than a solution with a pH of 6.0A) 1,000 B) 100 C) 10 D) 2 E) 0

52) The correct formula for hydrochloric acid is ___.A) HClO3 B) HCl C) HClO D) HClO2 E) H2Cl

53) The correct name for H2CO3 is ___ acid.A) carbonate B) carbonous C) hydrocarbonic D) carbonic E) hydrogen carbide

54) Calculate the unknown concentration of H3PO4 if 50.0mL was titrated to the end point with 16.50 mL of a

2.0 M NaOH solution according to the following acid-base titration.

H3PO4 (aq) + 3 NaOH(aq) → 2 H2O(l) + Na3PO4 (aq)A) 0.22 M B) 0.033 M C) 0.011 M D) 11 M E) 3 M

55) What volume of 0.124 M KOH titrant was used to neutralize 23.4 mL of 0.206 M HCl solution?A) 15.9 mL B) 38.9 mL C) 31.8 mL D) 1.00 × 104 mL E) 5.00 × 102 mL

UNIT 13: Chp. 10.1 – 10.4 Molecular Geometry and IMFs

56)

Which of the following is the correct electron-dot structure for CS2? A)

B)

C)

D)

E)

57)

Which of the following substances contains a nonpolar bond? A) N2 B) H2O C) NH3 D) NaCl E) MgF2

58)

A polar covalent bond is found in which of these compounds? A) H2O B) F2 C) NaCl D) N2 E) H2

59)

The number of electron lone pairs in the water molecule is ________. A) 3 B) 8 C) 1 D) 4 E) 2

60)

If the electronegativity difference between elements X and Y is 2.1, the bond between the elements X-Y is ___.

A)

ionic b) impossible C) metallic D) nonpolar covalent E) polar covalent

61)

The VSEPR theory allows us to determine the ________. A)

color of a compound B)

formula for a compound C)

shape of a molecule D)

bond type for a molecule E)

charge on an ion

62) The molecular shape of the ammonia molecule, NH3, is ___. A) trigonal pyramidal B) linear C) octagonal D) square E) hexagonal

63)

The water molecule has a molecular dipole with the negative portion A)

localized between the hydrogen atoms. B)

surrounding the molecule. C)

localized on one of the hydrogens. D)

pointing toward the oxygen atom. E)

pointing from the oxygen through the hydrogen atoms.

64)

The carbon tetrachloride molecule, CCl4, has the shape of a ________. A)

square

B)

cube

C)

tetrahedron

D)

sphere

E)

circle

65)

The bond dipole in the nitrogen-hydrogen bond points A)

from the nitrogen to the hydrogen. B)

at the observer. C)

at right angles to the bond. D)

in a circle surrounding the bond. E)

from the hydrogen to the nitrogen.

66)

The Lewis structures for methanol and ethanol are shown below. The difference in boiling point is most due to ___.

A)

methanol: boiling point = 65oC

ethanol: boiling point = 78oC

dipole-dipole interactions B)

hydrogen bondingC)

London dispersion forcesD)

Ion-dipole interacdtionsE)

Metallic bonding

67)

The main interactions between molecules of methane, CH4, are ________. A)

dispersion forces B)

dipole-dipole attractions C)

ionic bonds D)

hydrogen bonds E) none of the above

END2015-16 GenChem Final Review Equations/

ConstantsEquations: Constantsq = mSHΔT

KW = [H3O+][OH−] KW = 1.0 x 10−14

14 = pH + pOH Avogadro's Number 6.022

x 1023

pH = − log [H3O+]

pOH = − log [OH−] R = 0.0821 atm∙ Lmol ∙ K

M1V1 = M2V2

Molarity (M) = moles soluteliters solution SH H2 O = 4.184 J

g •C o

V 1

T 1 = V 2

T 2

V1P1 = V2P2

PT = P1 + P2 + P3...

V 1 P1

T 1 = V 2 P2

T 2

PV = nRT

V 1

n1 = V 2

n2

P1

T1 = P2

T2

KEY: A = Central Atom X = bonded atom E = lone pair of electrons

Electron Groups

Molecular Geometry Name

1 lone pair

2 lone pair

3 lone pair

5

See-Saw 4 bonds T-Shaped 3 bonds Linear 2 bonds

Standard Atmospheric Pressure Units:

1 atmosphere 1 atm

760 millimeters of mercury 760 mmHg

29.9 inches of mercury 29.9 in Hg

760 torricelli 760 torr

101,325 Pascal 101,325 Pa

101.325 kilopascal 101.325 kPa

14.70 pounds per square inch 14.70 lb/ in2

6

Square Pyramidal 5 bonds Square Planar 4 bondsSolubility Rules

Soluble Compounds Insoluble Compounds

all ammonium (NH4+) compounds

all Group I compounds all nitrates (NO3

─) compounds all acetate (CH3COO─) compounds all chlorate (ClO3

─) compounds all perchlorates (ClO4

─) chlorides - except Ag+ Pb2+ , Hg2

2+

bromides - except Ag+ Pb2+ , Hg22+

iodides - except Ag+ Pb2+ , Hg22+

sulfates (SO42─) - except Ag+, Pb2+ , Ba2+, Sr2+, Ca2+

sulfides – except Ba2+, Ca2+, Sr2+

carbonates (CO32─)

phosphates (PO43─)

hydroxides (OH─) – except Ba2+, Ca2+, Sr2+

2015/16 GenChem Final ReviewPart II: EXTENDED RESPONSE QUESTIONS: 30% of Final

Unit 7: Stoichiometry1. Use the following reaction to answer Questions 9 thru 11. For ALL questions, show ALL your work and circle your final answers. Be sure to include units with your answers.

Mg3N2(s) + 6 H2O (l) → 3 Mg(OH)2(s) + 2 NH3(g)

A. What is the limiting reactant of the above reaction if 20 g of Mg3N2 is reacted with 25 g of water?

20 g Mg3N2 × 1mol Mg3 N 2

100 .95 g × 2 mol N H 3

1mol Mg3 N 2 = 0.40 mol NH3

25 g H2O × 1mol H2 O18.02 g ×

2mol N H3

6mol H2 O = 0.69 mol NH3

B. What is the theoretical yield, in grams, of ammonia, NH3?

0.40 mol NH3 × 17.04 g NH 3

1 mol NH3 = 6.8 g NH3

C. If the actual yield of ammonia was 6.5 grams, what is the percent yield of this reaction?

6 . 5g actual yield6.8g theoretical yield × 100 = 96% yield

Unit 8: Thermochemistry

2. A 50.0 g of calcium chloride were dissolved in 200.0 mL of distilled water in a coffee-cup calorimeter according to the following equation:

CaCl2(s) → Ca2+(aq) + 2Cl – (aq) ΔHSol’n = – 82.9+ kJ/ mol

(a) Was the dissolving of CaCl2 an exothermic or endothermic process? Explain.

exothermic, because ΔHSol’n for the process was negative.

(b) If the temperature of the water in the coffee-cup calorimeter increased, did the chemicals release or absorb energy during the dissolving process? Justify your answer.

chemicals = released energy

the water absorbed the energy – this is what caused the temperature of the water to increase

Mg3N2 is limiting

(c) Calculate the amount of energychange caused when the 50.0 grams of calcium chloride dissolved. Show ALL work, circle final answer. Include units.

first: use molar mass to calculate the moles of CaCl2

50.0 g CaCl2 × 1 mole110.98g = 0.451 mol

second: use ΔHSol’n to calcualte the enrgy released

0.451 mol × −82 .9 kJmol = – 37.4 kJ

(d) Calculate the change in temperature, in oC, of the water. Show ALL work, circle final answer.

first: turn kilojoules into joules – 37.4 kJ = – 37,400 J

second: use q = mSHΔT to calcualte ΔT

q = mSHΔT → 37,400 J = 250.0 g (= 4 . 184 Jg •Co )ΔT =

35.8 oC Unit 9: Gas Laws

Use the above table of Vapor Pressure of Water to help answer question 7.

3. A 550-mL sample of hydrogen gas (H2) was collected over water at an atmospheric pressure of 105.7 kPa and a temperature of 50.0oC.

(a) Calculate the partial pressure, in kPa of hydrogen gas. Follow ALL math work rules!

PT = PH2 + PH2 O → 105.7 kPa = PH2 + 12.3 kPa

→ PH2 = 105.7 kPa – 12.3 kPa → PH2 = 93.4 kPa

(b) Convert the answer from (a) to pressure units of atmospheres. Follow ALL math work rules!

93.4 kPa × 1 atn101.3 kPa = 0.922 atm

(c) Calculate the number of moles of hydrogen gas collected. Follow ALL math work rules!

PV = nRT → (0.922 atm)(0.550 L) = n (0.0821 atm∙ Lmol ∙ K )(323 K)

→ n = 0.0191 mol H2

Unit 11: Solutions

For the following questions assume that the only materials available to you are those in the Materials List shown above.

4. (a) You have been asked by your teacher to make 100-mL of a 0.35 M solution of NaCl starting with solid NaCl.

(i) List any mathematical calculations you would need to make before you could start to make this solution.

moles of NaCl required, and

grams of NaCl required

(ii) Complete the calculation(s) from step 3(a)(i)

0.35 M is the same as 0 .35 moles NaCl1 liter , so……

…. 0 .35 molesCa Cl2

1 liter × 0.100 L = 0.035 moles NaCl required

NaCl = 58.44 g/ mol, so…..

... 0.035 mol NaCl × 58.44 g NaCl1mole = 2.0 grams of NaCl required

4. Continued:

(b) Explain how you would prepare this solution. The following lab equipment is available to you. Clearly identify the equipment and size being used.

Materials List: 100-mL burette 100-mL beaker 100-mL Erlenmeyer flask 100-mL graduated cylinder 100-mL volumetric flask 2-mL disposal pipettes

chemical scoop distilled water tap water electronic balance glass stirring rod hot plate w/ stir function

iron ring lab goggles and gloves powder funnel ring stands and clamp weigh boat

Write your procedure in bulleted form – failure to do so will result in a substantial loss of points.

Mass out 2.0 grams of NaCl using a chemical scoop, weigh boat, and electronic gram balance

Use a powder funnel to transfer the NaCl to a 100-mL volumetric flask

Add distilled water to the volumetric flask until it is about half full.

neutralization

water and salt

Vigorously swirl the volumetric flask until the NaCl is completely dissolved.

Fill the volumetric flask with distilled water until the bottom of the meniscus is even with the fill line on the flask

Unit 12: Acids and Bases5. (a) The reaction that occurs between and acid and a base is called a(n) ____________________ reaction.

(b) What products are always formed when an acid and a base react? ____________________

(c) Write the balanced chemical equation for the reaction between solid lead (II) hydroxide

and sulfuric acid. Be sure to include all phases of mater.

Pb(OH)2(s) + H2SO4(aq) → PbSO4(s) + 2 H2O(l)

Unit 13: Molecular Geometry and IMFs

6. Below is the Lewis structure for BrF4.

= individual bond dipoles

octahedraloctahedral(a) Name the electron pair (group) geometry: _____________________________

(b) Name the molecular geometry: _______________________________________

(c) Draw in ALL bond dipoles.

(d)Does this molecule have a molecular dipole? If YES, use an arrow to draw in the molecular dipole and then use the appropriate symbols to indicate the areas of partial positive and negative charge (if any.) If NO, explain why not.

This molecule does NOT have a molecular dipole. The individual bond dipoles are symmetrical and of equal magnitude and so they

“cancel out”.