Chemistry 1B Final Exam Review: Chem. 1B Portion:

Remember that your final will be an ACS Chemistry 1 Exam! This will include concepts from Chemistry 1A as well as Chemistry 1B. Our review today will only cover concepts that we learned during this semester. Please be sure to review your Chem 1A material.

This is my review for what I think will be on the exam. Do not use only this to study. I have not

seen the exam, so I cannot say for sure what will be on it. Some questions may have errors so be

sure to double check your answers with baseline. Continue to use your notes, textbook,

PowerPoints, homework, etc. to study. You got this!!!

Chapter 5: pg. 238

1. A sample of gas has an initial volume of 5.6 L at a pressure of 735 mmHg. If the volume of the gas is increased to 9.4 L, what is its pressure in mmHg?

P2 = 4.4 x 102 mmHg (ROUND was 437.87 mmHg)

Given: P1 = 735 mmHg, V1 = 5.6 L, V2 = 9.4 L

Find: P2

P1V1 = P2V2

2. A balloon contains 0.158 mol of gas and has a volume of 2.46 L. If an additional 0.113 mol of gas is added to the balloon (at the same temperature and pressure), what is its final volume?

V2 = 4.22 L

Given: n1 = 0.158 mol, V1 = 2.46 L, n2 = 0.113 mol

Find: V2

n1/V1 = n2/V2

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3. Which gas sample representation has the greatest pressure? Assume that all the samples are at the same temperature. Explain. Sample B has the greatest pressure because there are more molecules that can collide against the walls of the gas.

4. What is the pressure in a 10.0 L cylinder filled with 0.448 mol of nitrogen gas at a temperature of 315 K?

P = 1.16 atm

PV = nRT

R = 0.08206 atm*L*mol-1*K-1 or 0.0821

5. A piece of dry ice (solid carbon dioxide) with a mass of 28.8 g sublimes (converts from solid to gas) into a large balloon. Assuming that all of the carbon dioxide ends up in the balloon, what is the volume of the balloon at a temperature of 22oC and a pressure of 742 mmHg?

V = 16.2 L

PV = nRT

6. Use the molar volume of a gas at STP to determine the volume (in L) occupied by 33.6 g of neon at STP. V = 37.3 LPV = nRT

STP 1 mole of a substance occupies 22.4 L at 1 atm and 273.15 K Turn g into mol of Ne

o Multiply mol of Ne by 22.4 L

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Sample A: Sample C:Sample B:

7. A sample of gas has a mass of 38.8 mg. Its volume is 224 mL at a temperature of 55oC and a pressure of 886 torr. Find the molar mass of the gas. 4.00 g/molPV = nRT

Set up n = 0.0388g / x molo Solve for x

8. A gas mixture contains 1.25 g N2 and 0.85 g O2 in a 1.55 L container at 18oC. Calculate the mole fraction and partial pressure of each component in the gas mixture. XN2 = 0.627XO2 = 0.373PN2 = 0.687 atmPO2 = 0.409 atm X = n1/ntotal

Find P’s using PV = nRTPtotal = P1 + P2 + P3 + …

9. The graph shows the distribution of molecular velocities for two different molecules at the same temperature. Which molecule has the higher molar mass? Which molecule has the higher rate of effusion?

A has the higher molar mass, B has the higher rate of effusion

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500 1000 1500 2000 2500

Molecular velocity (ms-1)

Relative number of molecules

A

B

10.Methanol can be synthesized by the reaction:

CO (g) + 2 H2 (g) CH3OH (g)

What volume of H2 gas (in L), at 748 mmHg and 86oC, is required to synthesize 25.8 g CH3OH? How many liters of CO gas, measured to the same conditions, are required?

VH2 = 48.2 L

VCO = 24.1 L

Use stoichiometry to find # mol required for each reactant Then use PV = nRT

11.Ammonium carbonate decomposes upon heating according to the balanced equation:

(NH4)2CO3 (g) 2 NH3 (g) + CO2 (g) + H2O (g)

Calculate the total volume of gas produced at 22oC and 1.02 atm by the complete decomposition of 11.83 g of ammonium carbonate to the balanced equation.

V = 11.7 L

Chapter 7: pg. 329

12. The distance from the sun to Earth is 1.496 x 108 km. How long does it take light to travel from the sun to Earth?

499 s

c = 3.00 x 108 m/s

Simple conversion problem look at units!!!!!!!!!!!

13. List these types of electromagnetic radiation in order of increasing wavelength and increasing energy per photon:

Increasing wavelength: d, c, b, aIncreasing energy per photon: a, b, c, d

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14. A laser pulse with wavelength 532 nm contains 3.85 mJ of energy. How many photons are in the laser pulse?

1.03 x 1016 photons

E = hc/*lambda*

h = 6.626 x 1034 Js

c = 3.00 x 108 m/s

Divide the 3.85 mJ by the energy calculated using constants/equation above

15. What are the possible values of l for each value of n? a. 1 l = 0 b. 2 l = 0, 1c. 3 l = 0, 1, 2 d. 4 l = 0, 1, 2, 3

16. Which set of quantum numbers cannot occur together to specify an orbital? a. n = 2, l = 1, ml = -1b. n = 3, l = 2, ml = 0c. n = 3, l = 3, ml = 2d. n = 4, l = 3, ml = 0

17.Calculate the wavelength of light emitted when an electron in a hydrogen atom makes the transitions below. Indicate the region of the electromagnetic spectrum (infrared, visible, ultraviolet, etc.) where the light is found.

a. n = 2 n = 1

122 nm, UV

b. n = 5 n = 2

434 nm, visible

E = R (1/(n1)2 – 1/(n2)2)

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E = hc/*lambda*

R = 2.18 x 10-34 J

Chapter 8: pg. 375 Write the full orbital diagram for each element:

c. N

d. F

e. Mg

f. Al

18. Arrange these elements in order of increasing atomic radius: Ca, Rb, S, Si, Ge, F.

F, S, Si, Ge, Ca, Rb

19.Write the electron configuration for each ion:a. O2- [Ne]b. Br- [Kr]c. Sr2+ [Kr]

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d. Co3+ [Ar] 3d6

e. Cu2+ [Ar] 3d9

20. Arrange these elements in order of increasing first ionization energy: Si, F, In, N.

In, Si, N, F

21. Write orbital diagrams for each ion and determine if the ion is diamagnetic or paramagnetic

a. Cr3+ - paramagnetic

b. Ni2+ - paramagnetic

c. Fe3+ - paramagnetic

22. Arrange this isoelectronic series in order of decreasing radius: F-, Ne, O2-, Mg2+, Na+.

O2-, F-, Ne, Na+, Mg2+

23. Arrange these elements in order of increasing metallic character: Fr, Sb, In, Ba, Se.

S, Se, Sb, In, Ba, Fr

24.Choose the element with the more negative (more exothermic) electron affinity for each pair.

a. Na or Rb Nab. B or S Sc. C or N Cd. Li or F F

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Chapter 9: pg. 419

25.Write the Lewis structure for each molecule. a. PH3

Tetrahedral

b. SCl2

Tetrahedral

c. HI

Linear

d. CH4

Tetrahedral

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26.Write the Lewis symbols that represent the ions in each ionic compound.a. NaF

Na+ [F]-

b. CaO

Ca2+ [O]2-

c. SrBr2

Sr2+ 2[Br]-

d. K2O

2 K+ [O]2-

27.Explain the trend in the lattice energies of the alkaline earth metal oxides.

As the size of ions increaseso So does the distance between the metal cations and oxygen

anions Therefore magnitude of lattice energy decreases!!

o Due to potential energy decreasing as distance increasingo Charges are still the same (in same group)

28. Determine whether a bond between each pair of atoms would be pure covalent, polar covalent, or ionic.

a. Br and Br pure covalentb. C and Cl polar covalentc. C and S pure covalentd. Sr and O ionic bond

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29.Write the Lewis structure that obeys the octet rule for each molecule or ion. Include resonance structures if necessary and assign formal charges to each atom.

a. SeO2

b. CO32-

c. ClO-

d. NO2-

30.What are the formal charges of the atoms of the following molecule?

31.Write Lewis structures for each molecule or ion. Use expanded octets as necessary.

e. BCl3

f. NO2

g. PF5

h. I3-

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i. SF4

j. GeF4

32.Order these compounds in order of increasing carbon-carbon bond strength and in order of decreasing carbon-carbon bond length: HCCH, H2CCH2, H3CCH3.

Increasing bond strength H3CCH3, H2CCH2, HCCH

Decreasing bond length H3CCH3, H2CCH2, HCCH

33.Hydrogenation reactions are used to add hydrogen across double bonds in hydrocarbons and other organic compounds. Use average bond energies to calculate ∆ H rxn for the hydrogenation reaction. (Energies given at back of review)

C2H4 (g) + H2 (g) C2H6

-128 kJdeltaHrxn = Hproducts – Hreactants

34. Hydrogen, a potential future fuel, can be produced from carbon (from coal) and steam by this reaction:

C2 (s) + 2 H2O (g) 2 H2 (g) + CO2 (g)

Use the average bond energies to calculate the ∆ H rxn for this reaction. (Energies given at back of review)

-614 kJ

deltaHrxn = Hproducts – Hreactants

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35.Carbon ring structures are a common in organic chemistry. Draw a Lewis structure for each carbon ring structure, including any necessary resonance structures.

a. C4H8

b. C4H4

c. C6H12

d. C6H6

Chapter 10: pg. 474

36. Fill out the electron and molecular geometry chart below:

Electron Regions and

Hybridization

Bonding

Regions

Lone Pairs Electron

Geometry

Molecular Geometry Bond

Angle (o)

2, sp 2 0 Linear Linear 180

1 1 Linear 180

3, sp2 3 0 Trigonal planar Trigonal planar 120

2 1 Bent <120

4, sp3 4 0 Tetrahedral Tetrahedral 109.5

3 1 Trigonal pyramidal ~107

2 2 Bent ~104.5

5,sp3d 5 0 Trigonal

bipyramidal

Trigonal bipyramidal 90 axial

120 equi.

4 1 Seesaw <90 axial

<120 equi.

3 2 T-shaped <90

2 3 Linear ~180

6, sp3d2 6 0 Octahedral Octahedral 90

5 1 Square pyramidal <90

4 2 Square planar 90

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T-shaped

Linear

37. Determine the electron geometry, molecular geometry, and idealized bond angles for each molecule. In which cases do you expect deviations from the idealized bond angle?

a. PF3

Tetrahedral trigonal pyramidal ideally 109.5o BUT deviates to 107o

b. CHCl3

Tetrahedral tetrahedral ideally 109.5 with minimal deviation

c. SBr2

Tetrahedral bent ideally 109.5 BUT deviates to 104.5

d. CS2

Linear linear ideally 180 with no deviation

38. Determine whether the given molecules above are polar or nonpolar bonds.a. Polarb. Polarc. Nonpolard. Nonpolar

39.Determine whether each molecule is polar or nonpolar. a. SCl2 polarb. SCl4 polarc. BrCl5 polar

40.How many bonds can each of these atoms make without hybridization? a. Be 0b. P 3c. F 1

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41.Write orbital diagrams (boxes with arrows in them) to represent the electron configuration of carbon before and after sp3 hybridization. #

42.Which hybridization scheme allows the formation of at least one pi bond? a. sp3

b. sp2

c. sp3d2

43.Consider the structure of the amion acid alanine. Indicate the hybridization about each interior atom.

44. According to Molecular Orbital theory, which molecule or ion has the highest bond order? Highest bond energy? Shortest bond length?

C2, C2+, C2

-

C2- has the highest bond order, the highest bond energy, and the shortest bond

length

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To be used for 18:

To be used for 36 and 37:

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This is all that you will be given on the final exam:

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