CHEM 1331 - Exam 3 - Only Concepts Problems
Which of the following statements concerning the cubic unit cell is/are CORRECT? 1. For cubic unit cells, three cell symmetries occur: primitive cubic, face-centered cubic, and body-centered cubic. 2. The cell edges of a cubic unit cell are all equal in length. 3. The corner angles of a cubic cell are 90°. 1. 2. 3. 2 and 3 1,2 and 3
Correct Answer: 1, 2, and 3
This fossil fuel was formed from the remains of plants that were buried and exposed to high pressure and heat over time.
Correct Answer: A. coal
Consider the representations below of dispersion forces to answer the question below.. (I) NEED PHOTOS (II) NEED PHOTOS (III) NEED PHOTOS Reference: Ref 8-1 How many of the following statements are correct concerning the drawing? I. Each molecule induces a dipole onto the next molecule in close proximity. II. The phenomenon shown is relatively weak and short-lived. III. CH4 exhibits this type of interaction. IV. The forces that exist in this example are called London forces. Impartial Question -- maybe knowing the answer is enough if you are guessing.
Correct Answer: E. (4)
T or F: In exothermic reaction, potential energy stored in chemical bonds is being converted to thermal energy via heat.
Correct Answer: True
In which substance would the dispersion forces be weakest?
Correct Answer: a. He
A sample of oxygen gas has its absolute temperature halved while the pressure of the gas remained constant. If the initial volume is 400 mL, what is the final volume?
Correct Answer: c. 200 mL
Under which of the following sets of conditions will a sample of a real gas deviate most from ideal behavior?
Correct a. strong interparticle attractions, low temperature, high pressure
How many unit cells share an atom which is located at a corner (or lattice point) of a unit cell?
Correct: 8
Which of the species below would you expect to show the least hydrogen bonding? A) NH3 B) H2O C) HF D) CH4 E) all the same
D) CH4
For which of the following reaction(s) is the enthalpy change for the reaction not equal to ∆H˚f of the product? I. 2H(g) → H2(g) II. H2(g) + O2(g) → H2O2(l) III. H2O(l) + O(g) → H2O2(l) A) I B) II C) III D) I and III E) II and III
D) I and III
Which of the following would you expect to have the highest boiling point? A) F2 B) Cl2 C) Br2 D) I2 E) All of these have the same boiling point.
D) I2
The molecules in a sample of solid SO2 are attracted to each other by a combination of A) London forces and H-bonding. B) H-bonding and ionic bonding. C) covalent bonding and dipole-dipole interactions. D) London forces and dipole-dipole interactions. E) none of these
D) London forces and dipole-dipole interactions.
Which of the following should have the lowest boiling point? A) Na2S B) HF C) NH3 D) N2 E) H2O
D) N2
Which of the following is the correct order of boiling points for KNO3, CH3OH, C2H6, Ne? A) Ne < CH3OH < C2H6 < KNO3 B) KNO3 < CH3OH < C2H6 < Ne C) Ne < C2H6 < KNO3 < CH3OH D) Ne < C2H6 < CH3OH < KNO3 E) C2H6 < Ne < CH3OH < KNO3
D) Ne < C2H6 < CH3OH < KNO3
The coal with the highest energy available per unit burned is: A. Lignite. B. Subbituminous. C. Bituminous. D. Anthracite. E. They are equal in energy value.
D. Anthracite.
Which of the following is both a greenhouse gas and a fuel? A. carbon dioxide B. coal C. freon D. methane E. nitrogen
D. methane
Consider the following numbered processes: 1. A → 2B 2. B → C + D 3. E → 2D ΔH for the process A → 2C + E is A. ΔH1 + ΔH2 + ΔH3 B. ΔH1 + ΔH2 C. ΔH1 + ΔH2 - ΔH3 D. ΔH1 + 2ΔH2 - ΔH3 E. ΔH1 + 2ΔH2 + ΔH3
D. ΔH1 + 2ΔH2 - ΔH3
Which of the following intermolecular forces of attraction is the strongest?
hydrogen bonding
T or F: The results of coal gasification are products known as syngas and methane.
True
Which quantities are variables and which are fixed in the following: Charles's law
V and T are variables, n and P are fixed
Which of the following is both a greenhouse gas and a fuel?
methane
Which equation represents the number of atoms in a primitive cubic unit cell?
# of Atoms = 1/8 (8)
Of energy, work, enthalpy, and heat, how many are state functions? A. 0 B. 1 C. 2 D. 3 E. 4
C. 2
Use the following to answer questions 102-104: The molar volume of a certain form of solid lead is 18 cm3/mol. Assuming cubic closest packed structure, determine the following: 102. The number of Pb atoms per unit cell. A) 3 B) 4 C) 10 D) 12 E) 14 103. The volume of a single cell. A) 1.20 × 10^2 pm3 B) 1.20 × 10^4 pm3 C) 1.20 × 10^6 pm3 D) 1.20 × 10^8 pm3 E) none of these 104. The radius of a Pb atom. A) 1.74 pm B) 17.4 pm C) 174 pm D) 1740 pm E) none of these
102 -- B) 4 103 -- D) 1.20 × 10^8 pm3 104 -- C) 174 pm
Lithium chloride crystallizes in a face-centered cubic unit cell with chloride ions occupying the lattice points and lithium ions occupying octahedral holes. How many chloride ions surround each lithium ion in LiCl? 4 or 6
6
For the combustion of ethyl alcohol as described in the equation below, which of the following is true? I. The reaction is exothermic. II. The enthalpy change would be different if gaseous water were produced. III. The reaction is not an oxidation-reduction one. IV. The products of the reaction occupy a larger volume than the reactants. C2H5OH(l) + 3O2(g) → 2CO2(g) + 3H2O(l), ΔH = -1.37 × 103 kJ A) I, II B) I, II, III C) I, III, IV D) III, IV E) Only I
A) I, II
In which of the following groups of substances would dispersion forces be the only significant factors in determining boiling points? I. Cl2 II. HF III. Ne IV. KNO2 V. CCl4 A) I, III, V B) I, II, III C) II, IV D) II, V E) III, IV, V
A) I, III, V
Which of the following is most likely to be a solid at room temperature? A) Na2S B) HF C) NH3 D) N2 E) H2O
A) Na2S
Which of the following does not have a standard enthalpy of formation equal to zero at 25°C and 1.0 atm? A. F2(g) B. Al(s) C. H2O(l) D. H2(g) E. They all have a standard enthalpy equal to zero.
C. H2O(l)
Consider the reaction: 2ClF3(g) + 2NH3(g) → N2(g) + 6HF(g) + Cl2(g) When calculating the ΔH°rxn, why is the ΔHf° for N2 not important? A. Because nitrogen is in its standard elemental state and no energy is needed for this product to exist. B. Because any element or compound in the gaseous state requires a negligible amount of energy to exist. C. Because the products are not included when calculating ΔH°rxn. D. Because nitrogen is in its elemental state and does not contribute to the reaction itself. E. Two of the above statements explain why N2 is not important when calculating ΔH°rxn.
A. Because nitrogen is in its standard elemental state and no energy is needed for this product to exist.
Two metals of equal mass with different heat capacities are subjected to the same amount of heat. Which undergoes the smallest change in temperature? A. The metal with the higher heat capacity. B. The metal with the lower heat capacity. C. Both undergo the same change in temperature. D. You need to know the initial temperatures of the metals. E. You need to know which metals you have.
A. The metal with the higher heat capacity.
One of the main advantages of hydrogen as a fuel is that: A. The only product of hydrogen combustion is water. B. It exists as a free gas. C. It can be economically supplied by the world's oceans. D. Plants can economically produce the hydrogen needed. E. It contains a large amount of energy per unit volume of hydrogen gas.
A. The only product of hydrogen combustion is water.
This fossil fuel was formed from the remains of plants that were buried and exposed to high pressure and heat over time. A. coal B. natural gas C. diesel fuel D. propane E. gasoline
A. coal
A state function does not depend on the system's past or future. A. True B. False
A. True
In exothermic reaction, potential energy stored in chemical bonds is being converted to thermal energy via heat. A. True B. False
A. True
The specific heat capacities of metals are relatively low. A. True B. False
A. True
When a system performs work on the surroundings, the work is reported with a negative sign. A. True B. False
A. True
Given the equation S(s) + O2(g) → SO2(g), ΔH = -296 kJ, which of the following statement(s) is (are) true? I. The reaction is exothermic. II. When 0.500 mole sulfur is reacted, 148 kJ of energy is released. III. When 32.0 g of sulfur are burned, 2.96 × 10^5 J of energy is released
All are true. Why: I. True, because ΔH is negative. II. True, because you simply divide ΔH by two. III. True, because 32 g of sulfur is roughly one mole, so (296 kJ)(1000 J/kJ) = 2.96E5 J.
The following statements concerning petroleum are all true except:
All of its hydrocarbon chains contain the same number of carbon atoms.
Order the intermolecular forces (dipole-dipole, London Dispersion, ionic, and hydrogen-bonding) from weakest to strongest. A) dipole-dipole, London Dispersion, ionic, and hydrogen-bonding B) London Dispersion, dipole-dipole, hydrogen-bonding, ionic C) hydrogen-bonding, dipole-dipole, London Dispersion, and ionic D) dipole-dipole, ionic, London Dispersion, and hydrogen-bonding E) London Dispersion, ionic, dipole-dipole, and hydrogen-bonding
B) London Dispersion, dipole-dipole, hydrogen-bonding, ionic
Which of the following substances would you expect to have the lowest boiling point? A) diamond B) methane, CH4 C) sodium nitrate, NaNO3 D) glycerine, C3H5(OH)3 E) copper
B) methane, CH4
For the reaction H2O(l) → H2O(g) at 298 K, 1.0 atm, ΔH is more positive than ΔE by 2.5 kJ/mol. This quantity of energy can be considered to be A) the heat flow required to maintain a constant temperature. B) the work done in pushing back the atmosphere. C) the difference in the H-O bond energy in H2O(l) compared to H2O(g). D) the value of ΔH itself. E) none of these
B) the work done in pushing back the atmosphere.
Which of the following properties is (are) intensive properties? I. mass II. temperature III. volume IV. concentration V. energy A. I, III, and V B. II only C. II and IV D. III and IV E. I and V
C. II and IV
On a cold winter day, a steel metal fence post feels colder than a wooden fence post of identical size because: A. The specific heat capacity of steel is higher than the specific heat capacity of wood. B. The specific heat capacity of steel is lower than the specific heat capacity of wood. C. Steel has the ability to resist a temperature change better than wood. D. The mass of steel is less than wood so it loses heat faster. E. Two of the above statements are true.
B. The specific heat capacity of steel is lower than the specific heat capacity of wood.
A property that is independent of the pathway is called an intensive property. A. True B. False
B. False
The change in enthalpy can always be thought of as equal to energy flow as heat. A. True B. False
B. False
Consider a gas in a 1.0 L bulb at STP that is connected via a valve to another bulb that is initially evacuated. Answer the following concerning what occurs when the valve between the two bulbs is opened. What is true about the value of q? A. It is greater than zero. B. It is equal to zero. C. It is less than zero. D. More information is needed. E. None of these.
B. It is equal to zero.
When a nonpolar liquid displays a convex meniscus, which of the following explains this behavior?
B. The cohesive forces are stronger than the adhesive forces to the glass.
For a particular process q = -17 kJ and w = 21 kJ. Which of the following statements is false? A. Heat flows from the system to the surroundings. B. The system does work on the surroundings. C. ΔE = +4 kJ D. The process is exothermic. E. None of the above is false
B. The system does work on the surroundings.
For a particular process q = -17 kJ and w = 21 kJ. Which of the following statements is false? A) Heat flows from the system to the surroundings. B) The system does work on the surroundings. C) E = +4 kJ D) The process is exothermic. E) None of these is false.
C) E = +4 kJ
Which of the following statements about liquids is true? A) Droplet formation occurs because of the higher stability associated with increased surface area. B) Substances that can form hydrogen bonds will display lower melting points than predicted from periodic trends. C) London dispersion forces arise from a distortion of the electron clouds within a molecule or atom. D) Liquid rise within a capillary tube because of the small size lowers the effective atmospheric pressure over the surface of the liquid. E) The boiling point of a solution is dependent solely on the atmospheric pressure over the solution.
C) London dispersion forces arise from a distortion of the electron clouds within a molecule or atom.
Which substance involves no bonding forces except London dispersion forces? A) NaCl(l) B) HF(l) C) N2(s) D) H2O(l) E) K(s)
C) N2(s)
According to the first law of thermodynamics, the energy of the universe is constant. Does this mean that ΔE is always equal to zero? A) Yes, ΔE = 0 at all times, which is why q = -w. B) No, ΔE does not always equal zero, but this is due only to factors such as friction and heat. C) No, ΔE does not always equal zero because it refers to the system's internal energy, which is affected by heat and work. D) No, ΔE never equals zero because work is always being done on the system or by the system. E) No, ΔE never equals zero because energy is always flowing between the system and the surroundings.
C) No, ΔE does not always equal zero because it refers to the system's internal energy, which is affected by heat and work. Think q & w
On the basis of your knowledge of bonding in liquids and solids, arrange the following substances in order of highest to lowest melting temperature: NaCl, Na, Cl2, SiO2 A) Cl2, Na, NaCl, SiO2 B) Na, NaCl, Cl2, SiO2 C) SiO2, NaCl, Na, Cl2 D) NaCl, SiO2, Na, Cl2 E) SiO2, Na, NaCl, Cl2
C) SiO2, NaCl, Na, Cl2
The elements of group 5A, the nitrogen family, form compounds with hydrogen having the boiling points listed below: SbH3 -17°C, AsH3 -55°C, PH3 -87°C, NH3 -33°C The first three elements illustrate a trend where the boiling point decreases as the mass decreases; however, ammonia (HH3) does not follow the trend because of: A) dipole-dipole attraction. B) metallic bonding. C) hydrogen bonding. D) London dispersion forces. E) ionic bonding.
C) hydrogen bonding.
On a relative basis, the weaker the intermolecular forces in a substance, A) the greater its heat of vaporization. B) the more it deviates from ideal gas behavior. C) the greater its vapor pressure at a particular temperature. D) the higher its melting point. E) none of these
C) the greater its vapor pressure at a particular temperature.
Which one of the following statements is false? A. The change in internal energy, ΔE, for a process is equal to the amount of heat absorbed at constant volume, qv. B. The change in enthalpy, ΔH, for a process is equal to the amount of heat absorbed at constant pressure, qp. C. A bomb calorimeter measures ΔH directly. D. If qp for a process is negative, the process is exothermic. E. The freezing of water is an example of an exothermic reaction.
C. A bomb calorimeter measures ΔH directly.
In the lab, you mix two solutions (each originally at the same temperature) and the temperature of the resulting solution decreases. Which of the following is true? A. The chemical reaction is releasing energy. B. The energy released is equal to s × m × ΔT. C. The chemical reaction is absorbing energy. D. The chemical reaction is exothermic. E. More than one of these.
C. The chemical reaction is absorbing energy.
Consider the following processes: 2A → (1/2)B + C ΔH1 = 5 kJ/mol (3/2)B + 4C → 2A + C + 3D ΔH2 = -15 kJ/mol E + 4A → C ΔH3 = 10 kJ/mol Calculate ΔH for: C → E + 3D A. 0 kJ/mol B. 10 kJ/mol C. -10 kJ/mol D. -20 kJ/mol E. 20 kJ/mol
C. -10 kJ/mol
Consider the following processes: ΔH (kJ/mol) 3B → 2C + D -125 (1/2)A → B 150 E + A → D 350 Calculate ΔH for: B → E + 2C A. 325 kJ/mol B. 525 kJ/mol C. -175 kJ/mol D. -325 kJ/mol E. none of these
C. -175 kJ/mol
Which of the following statements is correct? A. The internal energy of a system increases when more work is done by the system than heat was flowing into the system. B. The internal energy of a system decreases when work is done on the system and heat is flowing into the system. C. The system does work on the surroundings when an ideal gas expands against a constant external pressure. D. All statements are true. E. All statements are false.
C. The system does work on the surroundings when an ideal gas expands against a constant external pressure.
Which of the following statements is(are) correct?
C. The system does work on the surroundings when an ideal gas expands against a constant external pressure.
Which of the following statements correctly describes the signs of q and w for the following exothermic process at P = 1 atm and T = 370 K? H2O(g) → H2O(l) A. q and w are negative. B. q is positive, w is negative. C. q is negative, w is positive. D. q and w are both positive. E. q and w are both zero.
C. q is negative, w is positive.
For a particular process q = 20 kJ and w = 15 kJ. Which of the following statements is true? A. Heat flows from the system to the surroundings. B. The system does work on the surroundings. C. ΔE = 35 kJ D. All of the above are true. E. None of the above are true.
C. ΔE = 35 kJ
The heat associated with a chemical reaction is measured in a device called a(n) __________.
Calorimeter
As pure molecular solids, which of the following exhibits dipole-dipole intermolecular forces: HBr, NBr3, SBr2, and CBr4?
Correct Answer: HBr, NBr3, and SBr2
Which one of the following decreases as the strength of the attractive intermolecular forces increases? A) The heat of vaporization. B) The normal boiling temperature. C) The extent of deviations from the ideal gas law. D) The sublimation temperature of a solid. E) The vapor pressure of a liquid.
E) The vapor pressure of a liquid.
If a student performs an endothermic reaction in a calorimeter, how does the calculated value of ΔH differ from the actual value if the heat exchanged with the calorimeter is not taken into account? A. ΔHcalc would be more negative because the calorimeter always absorbs heat from the reaction. B. ΔHcalc would be less negative because the calorimeter would absorb heat from the reaction. C. ΔHcalc would be more positive because the reaction absorbs heat from the calorimeter. D. ΔHcalc would be less positive because the reaction absorbs heat from the calorimeter. E. ΔHclac would equal the actual value because the calorimeter does not absorb heat.
D. ΔHcalc would be less positive because the reaction absorbs heat from the calorimeter.
Which of the following statements is/are true? I. q (heat) is a state function because ΔH is a state function and q = ΔH. II. When 50.0 g of aluminum at 20.0°C is placed in 50.0 mL of water at 30.0°C, the H2O will undergo a smaller temperature change than the aluminum. (The density of H2O = 1.0 g/mL, specific heat capacity of H2O = 4.18 J/g°C, specific heat capacity of aluminum = 0.89 J/g°C) III.When a gas is compressed, the work is negative since the surroundings are doing work on the system and energy flows out of the system. IV. For the reaction (at constant pressure) 2N2(g) + 5O2(g) → 2N2O5(g), the change in enthalpy is the same whether the reaction takes place in one step or in a series of steps. A. I, II, IV B. II, III C. II, III, IV D. II, IV E. All of the above statements are true.
D. II, IV
The molecules in a sample of solid SO2 are attracted to each other by a combination of
D. London forces and dipole-dipole interactions
The following statements concerning petroleum are all true except: A) It is a thick, dark liquid composed mostly of hydrocarbons. B) It must be separated into fractions (by boiling) in order to be used efficiently. C) Some of the commercial uses of petroleum fractions include gasoline and kerosene. D) It was probably formed from the remains of ancient marine organisms. E) All of its hydrocarbon chains contain the same number of carbon atoms.
E) All of its hydrocarbon chains contain the same number of carbon atoms.
Which statement regarding water is true? A) Energy must be given off in order to break down the crystal lattice of ice to a liquid. B) Hydrogen bonds are stronger than covalent bonds. C) Liquid water is less dense than solid water. D) Only covalent bonds are broken when ice melts. E) All of these are false.
E) All of these are false.
Hydrogen bonds account for which of the following observation? A) Hydrogen naturally exists as a diatomic molecule. B) Hydrogen is easily combustible with oxygen. C) Water molecules are bent or "V-shaped". D) Air is more dense than hydrogen gas. E) For its molar mass, water has a high boiling point.
E) For its molar mass, water has a high boiling point.
Consider the reaction H2(g) + (1/2)O2(g) → H2O(l) ΔH° = -286 kJ Which of the following is true? A) The reaction is exothermic. B) The reaction is endothermic. C) The enthalpy of the products is less than that of the reactants. D) Heat is absorbed by the system. E) The reaction is exothermic and the enthalpy of the products is less than that of the reactants.
E) The reaction is exothermic and the enthalpy of the products is less than that of the reactants.
The following statements concerning petroleum are all true except: A. It is a thick, dark liquid composed mostly of hydrocarbons. B. It must be separated into fractions (by boiling) in order to be used efficiently. C. Some of the commercial uses of petroleum fractions include gasoline and kerosene. D. It was probably formed from the remains of ancient marine organisms. E. All of its hydrocarbon chains contain the same number of carbon atoms.
E. All of its hydrocarbon chains contain the same number of carbon atoms.
Consider the reaction H2(g) + O2(g) → H2O(l) ΔH° = -286 kJ Which of the following is true? A. The reaction is exothermic. B. The reaction is endothermic. C. The enthalpy of the products is less than that of the reactants. D. Heat is absorbed by the system. E. Both A and C are true.
E. Both A and C are true.
Which statement is true of a process in which one mole of a gas is expanded from state A to state B? A. When the gas expands from state A to state B, the surroundings are doing work on the system. B. The amount of work done in the process must be the same, regardless of the path. C. It is not possible to have more than one path for a change of state. D. The final volume of the gas will depend on the path taken. E. The amount of heat released in the process will depend on the path taken.
E. The amount of heat released in the process will depend on the path taken.
Which of the following is not being considered as an energy source for the future? A. ethanol B. methanol C. seed oil D. shale oil E. carbon dioxide
E. carbon dioxide
If 5.0 kJ of energy is added to a 15.5-g sample of water at 10.°C, the water is A. boiling B. completely vaporized C. frozen solid D. decomposed E. still a liquid
E. still a liquid
All of the following statements about the greenhouse effect are true except: A. It occurs only on earth. B. The molecules H2O and CO2 play an important role in retaining the atmosphere's heat. C. Low humidity allows efficient radiation of heat back into space. D. The carbon dioxide content of the atmosphere is quite stable. E. A and D
E. A and D A. It occurs only on earth. D. The carbon dioxide content of the atmosphere is quite stable.
Consider the reaction: C2H5OH(l) + 3O2(g) → 2CO2(g) + 3H2O(l); ΔH = -1.37 × 103 kJ Consider the following propositions: I. The reaction is endothermic II. The reaction is exothermic. III. The enthalpy term would be different if the water formed was gaseous. Which of these propositions is (are) true? A. I B. II C. III D. I, II E. II, III
E. II, III
Which best explains the following trend? Element / b.p. (K) He 4 Ne 25 Ar 95 Kr 125 Xe 170 Don't have full question:
E. None of these. Would this be a london dispersion force trend? Best Answer: Yes. As they go down the column, they have more electrons and are correspondingly bigger and have more volume in which a temporary dipole can get established, giving the bigger ones higher boiling points.
In a(n) __________ process, heat is absorbed from the surroundings.
Endothermic
T or F: Heat and temperature are interchangeable terms.
False
T or F: In general, the density of a compound as a gas is closer in value to that of the compound as a liquid, than the density of the compound as a liquid is closer in value to that of the compound as a solid.
False
T or F: In the kinetic molecular theory we assume an ideal gas has no mass.
False
T or F: Natural gas is composed entirely of methane.
False
__________ involves the transfer of energy between two objects due to a temperature difference. Could be one or two words.
Heat
T or F: In exothermic reaction, potential energy stored in chemical bonds is being converted to thermal energy via heat.
True
T or F: Second row hydrides generally have higher than expected boiling points for their position on the periodic table.
True
This is reversed because of a picture. Just use for memorizing.
The unit cell in this two-dimensional crystal contains __________ Xs and __________ Os. A) 1,1 B) 2,1 C) 1,2 D) 4,1 E) 1,4 Answer: A) 1,1
T or F: The freezing of water is an exothermic process.
True
Which of the following statements is TRUE concerning a sample of gas held in a piston-cylinder apparatus if a change causes the piston to move toward the open end of the cylinder?
Work is being done BY the system
Which of the following statements about real gases is FALSE?
a. Real gas molecules differ most from ideal gas behavior at high temperature and low pressure.
At a given temperature and pressure, a sample of gas A is observed to diffuse twice as fast as an equal sized sample of a different gas, B. Based on this:
a. The molar mass of A is one fourth that of B
Propane, C3H8, will behave most like an ideal gas: at low temperature and high pressure or at high temperature and low pressure
at high temperature and low pressure
At very high pressures (~ 1000 atm), the measured pressure exerted by real gases is greater than that predicted by the ideal gas equation. This is mainly because d. of attractive intermolecular forces between gas molecules. or e. the volume occupied by the gas molecules themselves becomes significant.
e. the volume occupied by the gas molecules themselves becomes significant.
The __________ of a system is the sum of the kinetic and potential energies of all the particles in the system. Could be one or two words.
internal energy
Which of the following best describes the bonding between atoms in metals.
the valence electrons of each metal atom are delocalized over all of the atoms in the piece of metal
