CHE 105 Spring 2018 Exam 3

Transcription

1 CHE 105 Spring 2018 Exam 3 Your Name: Your ID: Question #: 1 Which three statements about energy are true? A. Energy cannot be created or destroyed. B. The three forms of energy are kinetic, potential, and mechanical. C. Energy can be converted from one form to another. D. Changes in matter, both physical and chemical, result in the matter either gaining or releasing energy. E. Potential energy is the energy associated with movement. F. Temperature is defined as the transfer of thermal energy between two bodies. Question #: 2 When ammonium nitrate dissolves in water at room temperature, the resultant solution becomes cold. Which two statements are true regarding this process? A. The reaction is exothermic. B. The reaction is endothermic. C. The kinetic energy of the atoms and molecules in the solution decreases. D. The kinetic energy of the atoms and molecules in the solution increases.

2 Question #: 3 Place the following in order of increasing (smallest to largest) wavelength. ultraviolet light gamma rays radio waves A. gamma rays <radio waves <ultraviolet light B. radio waves <ultraviolet light <gamma rays C. ultraviolet light <gamma rays <radio waves D. gamma rays <ultraviolet light <radio waves Question #: 4 Unlike humans, birds and bees can see ultraviolet light, which has an approximate wavelength of 324 nm. What is the frequency of this light? Report your answer with three significant figures. Do NOT include units in your answer. For numbers in scientific notation, use the format 2.22E2 for Hz 1. Question #: 5 How many photons are contained in a burst of yellow light (589 nm) that contains 609 kj of energy? A photons B photons C photons D photons

3 Question #: 6 The wavelength associated with a cell phone signal is 1 foot (12 inches). What is the energy associated with one photon from a cell phone? Write your answer with two significant figures. Do NOT include units in your answer. For numbers in scientific notation, use the format for 2.22E2 for joules 1. Question #: 7 What is the velocity of a marble (mass = 8.66 g) with a wavelength of meters? A m/s B m/s C m/s D m/s Question #: 8 Which statement is true regarding the quantum numbers of electrons? A. The principal quantum number defines the shape of the orbitals. B. The angular momentum quantum number defines how many electrons each individual orbital can hold. C. The magnetic quantum number defines the orientation of the orbital in space. D. The electron spin quantum number defines the relative distance of an electron from the nucleus.

4 Question #: 9 Which transition in a hydrogen atom represents the emission of a photon with the greatest energy? A. n = 2 to n = 1 B. n = 3 to n = 1 C. n = 6 to n = 3 D. n = 1 to n = 4 E. n = 2 to n = 5 Question #: 10 Which set of quantum numbers is allowed? A. (3, 0, 0, ½) B. (3, 3, 2, ½) C. (3, 1, 0, 1) D. (3, 0, 1, ½) Question #: 11 How many 4f orbitals can an atom of uranium contain? A. 5 B. 6 C. 7 D. 8

5 Question #: 12 Which two pairs of quantum numbers violate the Pauli exclusion principle? A. (3, 2, 2, ½) (3, 2, 1, ½) B. (3, 4, 2, ½) (3, 4, 2, ½) C. (2, 1, 2, ½) (2, 1, 2, ½) D. (2, 1, 0, ½) (2, 1, 0, ½) E. (1, 0, 0, ½) (1, 0, 0, ½) Question #: 13 Which neutral atom has the ground-state electron configuration [Kr]5s 2 4d 10? A. Zn B. Pd C. Sn D. Cd E. Te Question #: 14 A neutral atom of sulfur has 1 valence electrons and 2 core electrons. Report each answer as a whole number

6 Question #: 15 Based on their ground-state electron configurations, which two species are paramagnetic? A. Nb 3+ B. Sn 2+ C. O D. Ba E. Xe Question #: 16 Which set of quantum numbers describes the last (outermost) electron added to a zirconium (Zr) atom? A. (4, 3, 2, ½) B. (4, 2, 1, ½) C. (5, 3, 1, ½) D. (5, 2, 1, ½) Question #: 17 Which option has the elements given in order of increasing (smallest to largest) atomic radius? A. Cl <P <Ba B. As <O <Br C. Ar <Rb <Xe D. Ba <Hf <At

7 Question #: 18 Which statement is true regarding the size of atoms and ions? A. A magnesium ion will be larger than a neutral magnesium atom. B. A magnesium ion will be smaller than a neutral magnesium atom. C. A magnesium ion will be the same size as a neutral magnesium atom. Question #: 19 Which reaction represents the first ionization energy of oxygen? A. O + (g) + e O(g) B. O(g) + e O (g) C. O (g) O(g) + e D. O(g) O + (g) + e E. O (g) + e O 2 (g) Question #: 20 Consider the following ionization energies in kj, beginning with EI1 on the left. To which element do these ionization energies belong?. 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th A. silicon B. phosphorus C. sulfur D. chlorine E. argon

8 Question #: 21 The electron affinity (EA) of an atom is: A. greater than zero for all elements. B. the energy change that occurs when a gaseous atom accepts an electron to form an anion. C. a measure of the attraction an element has for its own electrons. D. numerically the same but with the opposite sign of the ionization energy. Question #: 22 Which electron configuration is correct for Sn 4+? A. [Kr]4d 10 B. [Kr]5s 2 4d 8 C. [Kr]5s 2 5d 8 D. [Kr]4d 8 5p 2 E. [Kr]5s 2 4d 6 5p 2 Question #: 23 Based on the general trends in electronegativities, which bond is most polar? A. C N B. C F C. C O D. C C E. F F

9 Question #: 24 How many non-bonding electrons are on nitrogen in the proper Lewis structure of nitrogen triiodide, NI3? A. one non-bonding electron B. two non-bonding electrons (one lone pair) C. zero non-bonding electrons D. three non-bonding electrons E. four non-bonding electrons (two lone pairs) Question #: 25 Which compound does not violate the octet rule? A. BeH2 B. NO2 C. SF6 D. BF3 E. SiO2 Question #: 26 Based on formal charges, which Lewis structure will be the most stable structure of CO2? A. The structure on the left would be most stable. B. The structure in the middle would be most stable. C. The structure on the right would be most stable.

10 Question #: 27 Based on lattice energies, which compound should have the highest melting point? A. aluminum nitride B. magnesium oxide C. sodium fluoride D. calcium sulfide E. rubidium iodide Question #: 28 What is the molecular structure of the nitrogen atom in the amino acid glycine? A. tetrahedral B. trigonal pyramidal C. bent D. trigonal planar

11 Question #: 29 What is the electron pair geometry (ep) and the molecular structure (ms) of the PCl4 + cation? A. ep = tetrahedral, ms = trigonal bipyramidal B. ep = trigonal bipyramidal, ms = seesaw C. ep = tetrahedral, ms = tetrahedral D. ep = octahedral, ms = square planar Question #: 30 Which two molecules are polar? A. CCl4 B. CH3Cl C. PCl3 D. [NH4] + E. SiH 4

12 DRAFT Do Not Use Until Posted. CHE 105 Spring 2018 Exam 3 - Confidential Your Name: Your ID: attachment_for_pubexamuid_lnxp xx_258.jpg Question #: 1 Which three statements about energy are true? A. Energy cannot be created or destroyed. B. The three forms of energy are kinetic, potential, and mechanical. C. Energy can be converted from one form to another. D. Changes in matter, both physical and chemical, result in the matter either gaining or releasing energy. E. Potential energy is the energy associated with movement. F. Temperature is defined as the transfer of thermal energy between two bodies. Question #: 2

13 When ammonium nitrate dissolves in water at room temperature, the resultant solution becomes cold. Which two statements are true regarding this process? A. The reaction is exothermic. B. The reaction is endothermic. C. The kinetic energy of the atoms and molecules in the solution decreases. D. The kinetic energy of the atoms and molecules in the solution increases. Question #: 3 Place the following in order of increasing (smallest to largest) wavelength. ultraviolet light gamma rays radio waves A. gamma rays <radio waves <ultraviolet light B. radio waves <ultraviolet light <gamma rays C. ultraviolet light <gamma rays <radio waves D. gamma rays <ultraviolet light <radio waves Question #: 4 Unlike humans, birds and bees can see ultraviolet light, which has an approximate wavelength of 324 nm. What is the frequency of this light? Report your answer with three significant figures. Do NOT include units in your answer. For numbers in scientific notation, use the format 2.22E2 for Hz E14 Question #: 5 How many photons are contained in a burst of yellow light (589 nm) that contains 609 kj of energy? A photons B photons

14 C photons D photons Question #: 6 The wavelength associated with a cell phone signal is 1 foot (12 inches). What is the energy associated with one photon from a cell phone? Write your answer with two significant figures. Do NOT include units in your answer. For numbers in scientific notation, use the format for 2.22E2 for joules E-25 Question #: 7 What is the velocity of a marble (mass = 8.66 g) with a wavelength of meters? A m/s B m/s C m/s D m/s Question #: 8 Which statement is true regarding the quantum numbers of electrons? A. The principal quantum number defines the shape of the orbitals. B. The angular momentum quantum number defines how many electrons each individual orbital can hold. C. The magnetic quantum number defines the orientation of the orbital in space. D. The electron spin quantum number defines the relative distance of an electron from the nucleus.

15 Question #: 9 Which transition in a hydrogen atom represents the emission of a photon with the greatest energy? A. n = 2 to n = 1 B. n = 3 to n = 1 C. n = 6 to n = 3 D. n = 1 to n = 4 E. n = 2 to n = 5 Question #: 10 Which set of quantum numbers is allowed? A. (3, 0, 0, ½) B. (3, 3, 2, ½) C. (3, 1, 0, 1) D. (3, 0, 1, ½) Question #: 11 How many 4f orbitals can an atom of uranium contain? A. 5 B. 6 C. 7 D. 8 Question #: 12 Which two pairs of quantum numbers violate the Pauli exclusion principle? A. (3, 2, 2, ½) (3, 2, 1, ½) B. (3, 4, 2, ½) (3, 4, 2, ½) C. (2, 1, 2, ½) (2, 1, 2, ½)

16 D. (2, 1, 0, ½) (2, 1, 0, ½) E. (1, 0, 0, ½) (1, 0, 0, ½) Question #: 13 Which neutral atom has the ground-state electron configuration [Kr]5s 2 4d 10? A. Zn B. Pd C. Sn D. Cd E. Te Question #: 14 A neutral atom of sulfur has 1 valence electrons and 2 core electrons. Report each answer as a whole number Question #: 15 Based on their ground-state electron configurations, which two species are paramagnetic? A. Nb 3+ B. Sn 2+ C. O D. Ba E. Xe Question #: 16 Which set of quantum numbers describes the last (outermost) electron added to a zirconium (Zr) atom?

17 A. (4, 3, 2, ½) B. (4, 2, 1, ½) C. (5, 3, 1, ½) D. (5, 2, 1, ½) Question #: 17 Which option has the elements given in order of increasing (smallest to largest) atomic radius? A. Cl <P <Ba B. As <O <Br C. Ar <Rb <Xe D. Ba <Hf <At Question #: 18 Which statement is true regarding the size of atoms and ions? A. A magnesium ion will be larger than a neutral magnesium atom. B. A magnesium ion will be smaller than a neutral magnesium atom. C. A magnesium ion will be the same size as a neutral magnesium atom. Question #: 19 Which reaction represents the first ionization energy of oxygen? A. O + (g) + e O(g) B. O(g) + e O (g) C. O (g) O(g) + e D. O(g) O + (g) + e E. O (g) + e O 2 (g) Question #: 20

18 Consider the following ionization energies in kj, beginning with EI 1 on the left. To which element do these ionization energies belong?. 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th A. silicon B. phosphorus C. sulfur D. chlorine E. argon Question #: 21 The electron affinity (EA) of an atom is: A. greater than zero for all elements. B. the energy change that occurs when a gaseous atom accepts an electron to form an anion. C. a measure of the attraction an element has for its own electrons. D. numerically the same but with the opposite sign of the ionization energy. Question #: 22 Which electron configuration is correct for Sn 4+? A. [Kr]4d 10 B. [Kr]5s 2 4d 8 C. [Kr]5s 2 5d 8 D. [Kr]4d 8 5p 2 E. [Kr]5s 2 4d 6 5p 2 Question #: 23

19 Based on the general trends in electronegativities, which bond is most polar? A. C N B. C F C. C O D. C C E. F F Question #: 24 How many non-bonding electrons are on nitrogen in the proper Lewis structure of nitrogen triiodide, NI 3?. A. one non-bonding electron B. two non-bonding electrons (one lone pair) C. zero non-bonding electrons D. three non-bonding electrons E. four non-bonding electrons (two lone pairs) Question #: 25 Which compound does not violate the octet rule? A. BeH 2 B. NO 2 C. SF 6 D. BF 3 E. SiO 2 Question #: 26 Based on formal charges, which Lewis structure will be the most stable structure of CO 2?

20 A. The structure on the left would be most stable. B. The structure in the middle would be most stable. C. The structure on the right would be most stable. Question #: 27 Based on lattice energies, which compound should have the highest melting point? A. aluminum nitride B. magnesium oxide C. sodium fluoride D. calcium sulfide E. rubidium iodide Question #: 28 What is the molecular structure of the nitrogen atom in the amino acid glycine? A. tetrahedral B. trigonal pyramidal C. bent D. trigonal planar

21 Question #: 29 What is the electron pair geometry (ep) and the molecular structure (ms) of the PCl + 4 cation?. A. ep = tetrahedral, ms = trigonal bipyramidal B. ep = trigonal bipyramidal, ms = seesaw C. ep = tetrahedral, ms = tetrahedral D. ep = octahedral, ms = square planar Question #: 30 Which two molecules are polar? A. CCl 4 B. CH 3 Cl C. PCl 3 D. [NH 4 ] + E. SiH 4