CHEM 107 Final Exam Study Guide and questions PDF

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Study guide for CHE 107 final exam from Spring 2018. Includes practice questions....

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MOLECULAR ORBITAL THEORY CHEM 105 FALL 2011 EXAM 4 58-60 QUESTION 58- which of the following best describes the bond in F2 using valence bond theory? A: The end-to-end overlap of a 2p orbital of one fluorine atom with a 2p

orbital of the other fluorine atom. B: The sideways overlap of a 2p orbital of one fluorine atom with a 2p

orbital of the other fluorine atom. C: The overlap of a 2s orbital of one fluorine atom with a 2s orbital of the other fluorine atom. D: he overlap of a 2s orbital of one flourine atom with the 2p orbital of the other fluorine atom. __________________________________________________________________ QUESTION 59- What is the bond order of F22‒? A: 0 B: 1/2 C: 1 D: 2 __________________________________________________________________

QUESTION 60. Complete the molecular orbital diagram for the N2+ ion and choose the FALSE statement.

1. The bond order of N2+ is 2.5. 2. The N2 + ion is paramagnetic. 3. The Bond order is lower than in the N2 molecule. 4. The N2 + ion is diamagnetic. WHICH ONE IS FALSE ____

__________________________________________________________________

BAND THEORY CHEM 107 FALL 2017 EXAM 1 14-17 Question #: 14

Fill in the blanks with the following choices: insulator, semiconductor, conductor. Each choice will be used only once.

Diagram A. represents a________ Diagram B. represents a___________ Diagram C. represents a_______ Only the material in diagram _______(A,B,C) can be doped to fine-tune its electrical properties. _________________________________________________________________________ Question #: 15

Which two of the following act as n-type semiconductors? A. silicon doped with gallium B. silicon doped with arsenic C. germanium doped with phosphorus

D. germanium doped with indium ____________________________________________________________________________ Question #: 16

1 _____ [Covalent, Ionic, Metallic] bonding gives rise to the properties of malleability, ductility, and conductivity of heat and electricity because electrons are 2 _______ [localized, delocalized] between individual metal nuclei. 1.___ 2. ___ ____________________________________________________________________________ Question #: 17

Which property of metals means they can be pounded into flat sheets? A. opaque B. ductile C. conductive D. malleable ____________________________________________________________________________

CHEM 107 SPRING 2017 EXAM 1 13, 16 Question #: 13

Select the two options that complete the statement below. Metals are good conductors of electricity because A. metallic bonds are directional. B. their electrons are delocalized over the entire metal crystal. C. their valence and conduction bands are energetically continuous. D. they are held together by ionic bonds.

13______

____________________________________________________________________________

Question #: 16

Which one of the following acts as a n-type semiconductor? A. silicon doped with gallium B. arsenic doped with gallium C. germanium doped with phosphorous D. phosphorous doped with arsenic ____________________________________________________________________________

CRYSTAL STRUCTURES CHEM 107 FALL 2017 EXAM 1 11,12 Question #: 11

Europium (152 g/mol) crystallizes in a body-centered cubic unit cell with an edge length of 458 pm. What is the density of europium?

A. 5.25 g/cm3 B. 10.5 g/cm3 C. 1.97 g/cm3 D. 22.8 g/cm3

____________________________________________________________________________ Question #: 12

Lanthanum ions (large, white spheres) are located on all corners and in a body-centered position while oxide ions (small, gray spheres) are located on all of the edges of a cubic unit cell. The number of lanthanum ions in the unit cell is ____ and the number of oxide ions is 2 . Use whole numbers as 1, 2, etc. for your answers and do not include units.

1_____ 2_______

CHEM 107 SPRING 2017 EXAM 1 10-11

Question #: 10

Iridium crystallizes in a face-centered cubic unit cell, as shown below, with an edge length of 383 pm. What is the density of Ir in g/cm3?

A. 22.7 g/cm3 B. 3.83 ×10-14 g/cm3 C. 5.78 g/cm3 D. 8.15 ×1029 g/cm3

11. A superalloy used in jet engines for its strength crystallizes as shown below, where the dark red spheres on the corners represent Al and the light gray spheres on the faces represent Ni. In this unit cell, there are 1 Al atom(s) and 2 Ni atom(s). Use whole numbers e.g., 1, 2, etc., for your answers.

1._______ 2._______ ____________________________________________________________________________

CHEM 107 FALL 2016 EXAM 1 12-14

Question #: 12

Which of these cubic unit cells has the greatest packing efficiency? _________ _________________________________________________________________________

A

B

C

____________________________________________________________________________

Question #: 13

The formula of the ionic compound with the unit cell below is 1______ List the formula in the order Pb# Zr# O#, with the lowest whole-number coefficient for each element (even if it is 1) and a space between each element.

1_____ ____________________________________________________________________________

14. Barium metal crystallizes in a body-centered cubic lattice, as shown below, with an edge length of 507 pm. The density of barium is 1.____ g/cm3. Report your answer with two significant digits. Do NOT include units in your answer.

1._______

____________________________________________________________________________

SPRING 2016 EXAM 1 12: Fill in the appropriate number of atoms per unit cell for the following crystalline atomic solids. A body-centered cubic unit cell contains 1.__ atom(s) per unit cell. A simple cubic unit cell contains 2.__ atom(s) per unit cell. A face-centered cubic unit cell contains 3.___ atom(s) per unit cell. 1._____ 2._____ 3.____ 13: Determine the formula for the rhenium oxide shown. Rhenium ions (red circles) are located on unit cell corners. Oxide ions (blue circles) are located on unit cell edges. A. Re2O3 B. Re3O C. ReO D. ReO3

14. Vanadium crystallizes in a body-centered cubic unit cell with a density 6.0 g/cm3. Calculate the edge length of the unit cell. A. 8.1 ×10–24 cm B. 3.0 ×10–8 cm C. 5.3 ×10–12 cm D. 7.1 ×10–9 cm

INTERNAL ENERGY, THERMAL ENERGY, CALOIMETRY, ENTHALPY CHEM 105 SPRING 2017 EXAM 3 1-12 Question #: 1

When energy flows into a system, the ΔE of the surroundings: A. is positive in value. B. is negative in value. C. is exactly zero. D. cannot be determined. ____________________________________________________________________________ Question #: 2

Which one is not a state function? A. pressure

B. temperature C. work

D. volume

E. energy ____________________________________________________________________________ Question #: 3

Select the two which correctly complete the sentence. The First Law of Thermodynamics states that A. the energy of the universe is decreasing over time. B. energy can be converted from one form to another. C. energy cannot be created or destroyed in a reaction.

D. chemical energy is a form of kinetic energy.

E. thermal energy is a form of potential energy.

____________________________________________________________________________ Question #: 4

What is the change in internal energy, ΔE, for a system that absorbs 571.2 kJ of heat and performs 77.7 kJ of work on the surroundings? 1.___ kJ Report your answer with one decimal place. Do NOT include units in your answer. 1______ Question #: 5

A cylinder with a moving piston expands from an initial volume of 0.250 L to a final volume of 0.750 L against an external pressure of 2.50 atm. How much work is done, in joules (J)? 1.___ L•atm = 101.3 J _____ Joules Report your answer with three significant figures. Do NOT include units in your answer. 1. ___________ Question #: 6

What amount of heat is necessary to raise the temperature of 57.8 grams of benzene by 57.0 oC ? The specific heat capacity of benzene is 1.05 J/g·oC. A. 1.61 kJ B. 16.6 kJ C. 2.59 kJ D. 2.86 kJ E. 3.46 kJ ____________________________________________________________________________

Question #: 7

When 2.02 g of glucose (molar mass = 180.2 g/mol) undergoes combustion in a bomb calorimeter, the temperature rises from 25.5 °C to 29.5 oC. What is ΔE for the combustion of glucose in kJ/mol glucose? The heat capacity of the bomb calorimeter is 4.90 kJ/oC. 1______ kJ/mol glucose

Report your answer with three significant figures. Do NOT include units in your answer. Use the format 2.22E2 or 2.22E-2 for answers in scientific notation. 1______

Question #: 8

For the reaction below, what is the enthalpy change for the decomposition of 765 g of PCl3? The molar mass of PCl3 is 137.32 g/mol. 4 PCl3(g) → P4(s) + 6 Cl2(g) ΔHorxn = +1207 kJ A. 2.31 × 103 kJ B. 4.33 × 103 kJ C. 6.72 × 103 kJ D. 1.68 × 103 kJ ____________________________________________________________________________ Question #: 9

When 75.0 mL of a 1.25 M HCl solution is mixed with a 100. mL of a 1.00 M NaOH solution in a constant-pressure calorimeter, the temperature of the resultant 175 mL solution increases from 23.0 °C to 33.0 °C. The final solution has a density of 1.00 g/mL. What is the enthalpy change (ΔH) of the reaction in kJ/mol of HCl? In this reaction NaOH is in excess. The specific heat capacity of the solution is 4.184 J/g•oC. 1____ kJ/mol HCl Report your answer with three significant figures. Do NOT include units in your answer. 1. ______

Question #: 10

From the equations and standard enthalpies of reaction given below, what is ΔHorxn for the decomposition of SO3 by the reaction: 4SO3(g)→4S(s)+6O2(g) ΔHorxn =?

Given: SO2(g) → S(s) + O2(g)

ΔHorxn = +296.8 kJ

&

2 SO2(g) + O2(g) → 2 SO3(g) ΔHorxn = –197.8 kJ

A. –494.6 kJ B. –692.4 kJ C. 1583 kJ D. 1142 kJ E. 993.1 kJ ____________________________________________________________________________ Question #: 11

What is the correct equation for the formation of sucrose (C12H22O11)? See attachment at end of exam to view a table of Standard Enthalpies of Formation.

A. 12 C(graphite) + 11 H2(g) + 5.5 O2(g) → C12H22O11(s) B. 12 C(graphite) + 22 H(g) + 11 O(g) → C12H22O11(s) C. 24 C(graphite) + 44 H2(g) + 11 O2(g) → C12H22O11(s) D. 1 C(graphite) + 1 H(g) + 1 O(g) → C12H22O11(s) ____________________________________________________________________________

Question #: 12

From the information provided, what is the standard enthalpy of formation, ΔHof , for IF(g)? IF7(g) + I2(g) → IF5(g) + 2 IF(g).

ΔHorxn = –89 kJ

ΔHof of IF7(g) = –941 kJ/mol ΔHof of IF5(g) = –840 kJ/mol

A. 24 kJ/mol B. 101 kJ/mol C. –95 kJ/mol D. –146 kJ/mol E. –191 kJ/mol ____________________________________________________________________________

CHEM 105 FALL 2016 EXAM 3 4-17 Question #: 4

Which statement is true of the internal energy of the system and its surroundings following a process in which ΔEsys = +100kJ? A. The system and surroundings both lose 100 kJ of energy. B. The system and surroundings both gain 100 kJ of energy. C. The system loses 100 kJ and the surroundings gain 100 kJ of energy. D. The system gains 100 kJ and the surroundings lose 100 kJ of energy. ____________________________________________________________________________

Question #: 5

Which of the following states the first law of thermodynamics? A. Energy can be created and destroyed. B. Energy can be destroyed but not created. C. Energy cannot be created or destroyed.

D. Energy cannot be converted from one form to another. ____________________________________________________________________________ Question #: 6

A chemical reaction releases heat and produces a net increase in the volume of gas. If the chemical reaction is the system, what are the signs of heat (q) and work (w) for the system? A. q = +, w = + B. q = –, w = – C. q = –, w = + D. q = +, w = – ____________________________________________________________________________ Question #: 7

If a system absorbs 325 J of energy from the surroundings while it does 92.0 J of work, what is the change in internal energy of the system? Report your answer with three significant figures. Do NOT include units in your answer. 1.____J ____________________________________________________________________________

Question #: 8

How much heat is required to raise the temperature of 155 g of copper metal from 33.00oC to 75.00oC? The specific heat capacity of copper is 0.385 J/g•oC. A. 16.2 kJ B. 2.51×103 J C. 2.60×103 kJ D. 6.44×103 J ____________________________________________________________________________ Question #: 9

Which statement is false? 1. An exothermic reaction releases heat to the surroundings. 2. Enthalpy is the sum of a system's internal energy and the product of pressure and

volume under constant-pressure conditions. 3. The change in internal energy for a reaction is not related to the change in

enthalpy of the

reaction. 4. The change in enthalpy for a reaction can be measured using a coffee-cup

calorimeter. 9-____________ ____________________________________________________________________________ Question #: 10

A 100.0 g iron bar, initially at 58.35 C, is submerged in 125 g of water, initially at 25.00 C, in an insulated container. What is the final temperature of both substances at thermal equilibrium? The specific heat capacity of iron is 0.449 J/g•C and the specific heat capacity of water is 4.18 J/g•C. Report your answer with three significant figures. Do NOT include units in your answer. 1 _____C Question #: 11

What mass of CH4(g) must burn to release 452 kJ of heat? A. 9.04 g B. 4.60 g C. 28.0 g D. 11.7 g ____________________________________________________________________________ Question #: 12

When 0.514 g of biphenyl (C12H10) undergoes comubustion in a bomb calorimeter, the temperature increases from 25.80 °C to 29.40 C. If the heat capacity of the bomb calorimeter is 5.86 kJ/°C, what is the change in internal energy of the combustion of biphenyl in kJ? Report your answer with two significant figures. Report your answer in scientific notation with the format 2.2E2 or 2.2E-2. Do NOT include units in your answer.

The first blank should include only the sign (+ or –). The second blank should include only a number without a sign. 1 _____indicate + or –

2 ____ kJ

____________________________________________________________________________ Question #: 13

For which two of the following reactions is the change in enthalpy equal to the change in internal energy? A. C(s) + O2(g) → CO2(g) B. 2 H2O(l) → 2 H2(g) + O2(g) C. 4 C3H5N3O9(l) → 12 CO2(g) + 10 H2O(g) + 6 N2(g) + O2(g) D. N2O4(g) + 4 H2(g) → N2(g) + 4 H2O(g) E. 2 C8H18 (l) + 25 O2(g) → 18 H2O(g) + 16 CO2(g)

____________________________________________________________________________ Question #: 14

Magnesium metal reacts with hydrochloric acid according to the balanced equation below: Mg(s) + 2HCl(aq) →MgCl2(aq) +H2(g) When 0.254 g of Mg metal is completely reacted with enough HCl(aq) to produce 2.00 × 102 mL of solution in a constant-pressure calorimeter, the temperature of the solution was observed to rise from 25.00oC to 32.20oC. What is the change in enthalpy for the reaction (as written) per mole of Mg(s)? Use 1.00 g/mL for the density of the solution, and 4.18 J/g•C for the specific heat capacity of the solution. A. +6.02×103 kJ/mol B. -5.76×105 J/mol C. +7.64 J/mol D. -73.2 kJ/mol ____________________________________________________________________________ Question #: 15

Consider the following reaction. PCl5(s) → PCl3(g) + Cl2(g) ΔH° = +157 kJ What is the change in enthlalpy for the reaction below? 2PCl3(g) + 2Cl2(g) → 2PCl5(s) ΔH° = ?

A. +157 kJ B. –2.46×104 kJ C. –314 kJ D. +78.5 kJ ____________________________________________________________________________

Question #: 16

Consider the following reactions. CH2CO(g) + 2 O2(g) →2 CO2(g) + H2O(g) ΔH = –981.1 kJ CH4(g) + 2 O2(g) →CO2(g) + 2 H2O(g) ΔH = –802.3 kJ Find the enthalpy change for the reaction below. CH2CO(g) + 3 H2O(g) →2 CH4(g) + 2 O2(g) A. 623.5 kJ B. 1783.6 kJ C. –178.8 kJ D. –1293.0 kJ ____________________________________________________________________________ Question #: 17

Given the following data, calculate the enthalpy of formation of CCl4(g). CH4(g) + 4 Cl2(g) → CCl4(g) + 4 HCl(g) ΔHo = –391 kJ ΔHof of CH4(g) = –74.6 kJ/mol ΔHof of CCl4(g) = 1 kJ/mol ΔHof of HCl(g) = –92.3 kJ/mol Report your answer with three significant figures. Do NOT include units in your answer. 1. ______

____________________________________________________________________________

CHEM 105 SPRING 2016 EXAM 3 3-11 Question #: 3 Which of the following statements is correct for a system that undergoes a change with negative q (heat) and positive w (work)? A. Work is done by the system while heat is lost to the surroundings. B. Work is done on the system while heat is lost to the surroundings. C. Work is done on the system while heat is absorbed by the system. D. Work is done by the system while heat is absorbed by the system. ______________________________________________________ Question #: 4 Calculate the internal energy change for a system that does 422 J of work while losing 227 J of energy as heat. A. +649 J B. –649 J C. –195 J D. +195 J ______________________________________________________ Question #: 5 A 10.0 g metal block at 65.0 °C is placed in 50.0 mL of water at 22.0 °C. The final temperature of both is 26.5 °C. The specific heat capacity of the metal is 1 J/g·°C. The density of water is 1.00 g/mL. The specific heat capacity of water is 4.18 J/g·°C. Report your answer with two significant figures and without units. 1. ________ ______________________________________________________

Question #: 6 The work done (w) when the volume of a system changes from 3.50 L to 2.40 L at a

constant pressure of 2.00 atm is 1 J. 101.3 J = 1.000 L•atm Report your answer with two significant digits, in the form 2.2E2 or 2.2E-2 if you use scientific notation. 1. ________ ______________________________________________________

Question #: 7 Dissolving 6.00 g of CaCl2 in 300. mL of water causes the temperature of the solution to increase by 3.43 °C. Determine ΔH for the reaction CaCl2(s) →Ca2+(aq) + 2 Cl–(aq). The specific heat of the solution is 4.18 J/g·°C The density of water is 1.00 g/mL. The calorimeter absorbs no significant amount of heat. A. –79.6 kJ B. 79.6 kJ C. 44.0 kJ D. –44.0 kJ ______________________________________________________ Question #: 8 Select all of the true statements about enthalpy (H) and internal energy (E). A. Enthalpy change is the heat evolved by a chemical reaction at constant pressure. B. Enthalpy change is the sum of the heat released and the work performed by a chemical

reaction. C. The internal energy change is the heat evolved by a chemical reaction at constant pressure. D. The internal energy change is the sum of the heat released and the work performed by a chemical reaction. ______________________________________________________

Question #: 9 In chemical reactions 1 and 2, reactant (R) is converted to product (P). The figures show the enthalpy of each system as the reaction proceeds towards completion.

Identify eac...