CHM 110 Week 5 Quiz

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CHM 110 Week 5 Quiz
CHM 110 Week 5 Quiz
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CHM 110 Week 5 Quiz

Complete the attached quiz and post in the classroom link.  Please hightlight the entire correct answer.  Please also use the Word document to submit.

  1. What is the relationship between science and technology?

A. Science is the experimental investigation and explanation of natural phenomena, or knowledge from experience, while technology applies this scientific knowledge.
B. Science investigates and explains natural phenomena, and technology feeds science and supplies it with ideas.
C. Science applies what is learned through technology.
D. Science promotes change in society and technology ensures that those changes are positive.
E. Science and technology are one and the same.

 

  1. It has been found that the pressure of air is the sum of the partial pressures of the gases found in the air, such as nitrogen, oxygen, and carbon dioxide. In terms of the scientific method, this is an example of

A. a law
B. an experiment
C. a theory
D. a prediction
E. a cyclic process

 

  1. Which of the following choices demonstrates the law of constant composition?

 

A. When 20.0 g of nitrogen and 32.0 g of oxygen are combined and allowed to react in two separate experiments, both times the product contains 14.0 g of nitrogen and 32.0 g of oxygen.
B. When 14.0 g of nitrogen and 32.0 g of oxygen are mixed and react, there is no measurable change in mass during the reaction.
C. Nitrogen and oxygen gases are mixed to produce a sample consisting of 20.0 g of nitrogen and 32.0 g of oxygen.
D. Nitrogen and oxygen are gases found in air ­ nitrogen is approximately 79% of air and oxygen is approximately 21%.

 

 

 

  1. Without doing any calculations, which of the following do you think represents the atomic weight of a naturally occurring sample of magnesium? On Earth, magnesium occurs as a mixture of three isotopes: 24Mg with an atomic weight of 23.99 and a percent abundance of 78.70%; 25Mg with an atomic weight of 2499 and a percent abundance of 10.13%; and 26Mg with an atomic weight of 25.98 and a percent abundance of 11.17%.

 

A. 23.99
B. 25.98
C. 25.08
D. 24.31
E. 24.99

 

5. Which type of electromagnetic radiation has the largest energy?

A. Ultraviolet      rays
B. Infrared radiation
C. Gamma rays
D. Microwaves
E. Radio waves

 

  1. What is the maximum number of electrons that a d subshell can hold?

 

A. Ten
B. Two
C. Six
D. Eight
E. Fourteen

 

  1. When you compare the atomic size of silicon (Si) to that of phosphorus (P)

 

A. silicon is a larger atom than phosphorus because phosphorus has one more proton than silicon, thereby increasing the attraction for all electrons and shrinking the orbit.
B. silicon is a larger atom than phosphorus because phosphorus is in the period above silicon in the periodic table.
C. silicon is a smaller atom than phosphorus because phosphorus is in the period below silicon in the periodic table
D. silicon and phosphorus are the same size because they are in the same period of the periodic table.
E. silicon is smaller than phosphorus because silicon has only 14 protons and electrons while phosphorus has 15 of each.

 

  1. Valence shell electron pair repulsion (VSEPR) theory is based on which of the following concepts?

 

A. The concept that valence electrons repel each other due to their small size.
B. The concept that valence electrons are attracted to protons found in the nucleus of the atom, since electrons are negatively charged while protons carry a positive charge.
C. The concept that electrons in a molecule will repel each other due to their negative charge.
D. The concept that electrons are very large particles and occupy a large amount of space inside a molecule.
E. The concept that valence electrons are attracted to the nucleus of an atom and therefore will spread as little as possible from each other.

 

  1. The polarity of a molecule depends on the polarity of the bonds within the molecules as well as the shape of the molecule. All of the following statements are true concerning the polarity of a molecule EXCEPT

 

A. molecules with symmetrically arranged polar bonds to the same element are nonpolar because the individual bond dipoles cancel out.
B. linear molecules formed from only two atoms are nonpolar if they are formed from two atoms of the same element.
C. linear molecules formed from only two atoms are polar if they are formed from two atoms of different elements with a difference in electronegativity.
D. polar molecules have three-dimensional shapes while nonpolar molecules are two-dimensional or flat.
E. molecules with symmetrically arranged polar bonds to different elements are polar as long as the individual bond dipoles do not cancel out

 

 

 

  1. Which molecule, H2S or H2Se, is more polar and why?

 

A. H2S is more polar than H2Se because H2S has greater dipole-dipole forces than H2Se since the H-S bond is more polar than the H-Se bond.
B. H2Se is more polar than H2S because H2Se has greater dipole-dipole forces than H2S since the H-Se bond is more polar than the H-S bond.
C. H2S is more polar than H2Se because H2S has greater dipole-dipole forces than H2Se, since H2S has two lone pairs of electrons and H2Se does not.
D. H2Se is more polar than H2S because H2Se has greater dipole-dipole forces than H2S, since H2Se has two lone pairs of electrons and H2S does not.
E. H2Se is more polar than H2S because H2Se has a higher molecular mass than H2S, and molecular mass is the most important factor in determining polarities of molecules.

 

  1. Hydrogen bonding occurs whenever hydrogen is directly bonded to a small highly electronegative atom. Select the elements that may be involved in hydrogen bonding.

    C, N, O, F, Si, Cl

 

A. F and Cl
B. C and N
C. Si and F
D. N and O
E. O and C

 

  1. Select the type of intermolecular force – or forces – found between molecules of ammonia (NH3).

    1. London forces.

    2. Hydrogen bonds.

    3. Ionic bonds.

    4. Covalent bonds.

 

A. 1 and 2
B. 1
C. 2
D. 3
E. 4

 

 

 

 

13.  The gas in a pressurized container is at 1200 millimeters of mercury. What is the gas pressure in atmospheres

A. 2.38 atm
B. 2.12 atm
C. 1200 atm
D. 1.58 atm
E. 3048 atm

 

  1. What must the temperature (in °C) be, if 50 grams of O2 in a 10.0 L container has a pressure of 5.0 atm.

 

A. 117 °C
B. 390 °C
C. 273 °C
D. 12.2 °C
E. -261 °C

 

  1. Le Chatelier’s principle states that if a reaction at equilibrium is disturbed, the reaction will return to equilibrium by shifting in such a direction as to partially undo the disturbance. The following are examples of methods used in disturbing the equilibrium EXCEPT

 

A. Adding more of one reactant to change the concentration of that reactant
B. Removing product molecules, thereby decreasing the concentration of products.
C. Adding a small amount of substance that does not react with any of the reactants or products.
D. Increasing the temperature if the reaction is exothermic.
E. Increasing the temperature if the reaction is endothermic.

 

 

 

 

  1. Stable isotopes have a ratio of neutrons to protons that form a compact band known as the band of stability. All of the following statements about the band of stability are true EXCEPT

 

A. For elements with atomic numbers of 20 or less, the neutron to proton ratio is close to 1 for isotopes within the band of stability.
B. For elements with atomic numbers greater than 20, the neutron to proton ratio increases until it reaches a ratio of 2 for isotopes within the band of stability.
C. The band of stability stops and then reappears as a little island at the top, corresponding to super heavy elements that have been predicted to be stable.
D. Isotopes are considered to be stable if they are nonradioactive isotopes or radioactive isotopes with measurable half-lives.
E. The neutron to proton ratio increases after element #20 because once a nucleus has 20 or more protons, it has become so positive that additional neutrons are required to help keep it together.

 

 

17.  Cobalt-60 is a radioactive isotope used in radiation therapy for cancerous tumors. Its half-life is 5.27 years. If a sample of cobalt-60 contains 50 µg, how much of the sample remains after 21.1 years?

 

A. 2.37 µg

B. 12.5 µg
C. 0.0 µg
D. 9.49 µg
E. 3.13 µg

  1. When an isotope has an n/p ratio that is not within the band of stability, it undergoes a nuclear change called radioactive decay. All of the following statements about radioactive decay are true EXCEPT

 

A. The radioactive decay that certain unstable isotopes undergo to become stable is a spontaneous process.

B. Some of the isotopes between atomic number 84 and 102 are unstable and undergo radioactive decay, while other isotopes within that range are stable and are therefore not radioactive.
C. Isotopes below the path of full stability have an n/p ratio that is too small–too few neutrons–so these isotopes could become stable by converting one or more of the protons into neutrons.
D. All of the isotopes between atomic number 84 and 102 are unstable and undergo radioactive decay.