test questions

• 1.         What is the oxidation number of nitrogen in NH3?    

  A)    0

  B)     -1

  C)    -3

  D)    -2

  E)     none of the above

  c
• 1.         What element is being reduced in the following redox reaction?

  Cr(OH)4⁻(aq) + ClO⁻(aq) → CrO42-(aq) + Cl⁻(aq)

  A)    H   

  B)     Cl   

  C)    Cr  

  D)    O

  E)     None; this is not a redox reaction.

   

  b
• 1.         What substance is the oxidizing agent in the following redox reaction?

   

  Zn2+(aq) + Mg(s) → Mg2+(aq) + Zn(s)

   

  A)    Zn

  B)     Mg2+ 

  C)    Zn2+

  D)    Mg 

  E)     none of the above

   

  c
•  

  1.         Define kinetic energy.          

  A)    energy associated with the temperature of an object

  B)     energy associated with the motion of an object

  C)    energy associated with the force of an object

  D)    energy associated with the gravity of an object

  E)     energy associated with the position or composition of an object

  b
• 1.         Which of the following signs on q and w represent a system that is doing work on the surroundings, as well as releasing heat to the surroundings?

  A)    q = +, w = -

  B)     q = -, w = +

  C)    q = +, w = +

  D)    q = -, w = - 

  E)     None of these represent the system referenced above.

   

  d
• 1.         Which of the following (with specific heat capacity provided) would show the largest temperature change upon gaining 100.0 J of heat?           

  A)    25.0 g Ag, CAg = 0.235 J/g°C

  B)     25.0 g granite, Cgranite = 0.79 J/g°C

  C)    25.0 g Au, CAu = 0.128 J/g°C

  D)    50.0 g Al, CAl = 0.903 J/g°C

  E)     50.0 g Cu, CCu = 0.385 J/g°C

  c
• 1.          Calculate the amount of heat (in kJ) required to raise the temperature of a 79.0 g sample of ethanol from 298.0 K to  385.0 K. The specific heat capacity of ethanol is 2.42 J/g∙K.

  A)    57.0 kJ        

  B)     28.4 kJ        

  C)    12.9 kJ        

  D)    16.6 kJ        

  E)     73.6 kJ

  d
• 1.          For a process at constant volume,    

  A)    ΔE = ΔH.

  B)     ΔE = q and w = 0.     

  C)    ΔH = q.

  D)    ΔE = w and q = 0.     

  all of the above are true

  b
• 1.         Which of the following statements about energy is FALSE?

  A)    The total energy of the universes remains constant.

  B)     Energy is the capacity to do work.

  C)    Systems tend to change in order to lower their potential energy. 

  D)    Kinetic energy is the energy associated with its position or composition.

  E)     Energy can be converted from one type to another.

   

   

  d
• 1.         Calculate the change in internal energy (ΔE) for a system that is giving off 25.0 kJ of heat and is changing from 12.00 L to 6.00 L in volume at 1.50 atm pressure. (Remember that 101.3 J = 1 L∙atm) 

  A)    -25.9 kJ       

  B)     937 kJ         

  C)    +25.9 kJ       

  D)    -24.1 kJ       

  E)     -16.0 kJ

  d
• 1.         Select the FALSE statement regarding the symbol "ΔH."

  A)    ΔH is a state function.

  B)     ΔH can be called enthalpy change.

  C)    ΔH represents the difference between the energy used in breaking bonds and the energy released in forming bonds in a chemical reaction.

  D)    ΔH can be called heat of reaction.

  E)     ΔH is positive for an exothermic reaction.

  e
•  

  1.         How much energy is evolved (aka released) during the formation of 98.7 g of Fe, according to the reaction below?

  Fe2O3(s) + 2 Al(s) → Al2O3(s) + 2 Fe(s)   ΔH°rxn = -852 kJ

   

  A)    241 kJ

  B)     753 kJ

  C)    4.20 × 103 kJ

  D)    482 kJ

  E)     1.51 × 103 kJ

  b
• 1.         Use the standard reaction enthalpies given below to determine ΔH°rxn for the following reaction

  P4(g) + 10 Cl2(g) → 4PCl5(s)                        ΔH°rxn = ?

  Given:

              PCl5(s) → PCl3(g) + Cl2(g)              ΔH°rxn = +157 kJ

              P4(g) + 6 Cl2(g) → 4 PCl3(g)             ΔH°rxn = -1207 kJ    

   

  A)    -1050. kJ

  B)     -1364 kJ      

  C)    -1786 kJ      

  D)    -1835 kJ      

  E)     -2100. kJ

  d
• 1.         Use the bond energies provided to estimate ΔH°rxn for the reaction below.

  PCl3(g) + Cl2(g) → PCl5(l)         ΔH°rxn = ?

  Bond          Bond Energy (kJ/mol)

  Cl-Cl          243

  P-Cl             331

   

  A)    -905 kJ        

  B)     -662 kJ        

  C)    -419 kJ

  D)    -243 kJ        

  E)     -67 kJ          

  c
• 1.         Use the information provided to determine ΔH°rxn for the following reaction

  CH4(g) + 4 Cl2(g) → CCl4(g) + 4 HCl(g)                ΔH°rxn = ?

   

                    ΔH°f (kJ/mol)   

  CH4(g)       -75

  CCl4(g)       -96

  HCl(g)        -92  

   

  A)    +113 kJ        

  B)     -113 kJ        

  C)    +79 kJ         

  D)    -389 kJ        

  E)     -71 kJ

  d
• 1.         The volume of a gas with a pressure of 1.2 atm increases from 1.0 L to 4.0 L. What is the final pressure of the gas, assuming constant temperature and amount of gas?        

  A)    1.0 atm       

  B)     1.2 atm       

  C)    0.30 atm      

  D)    4.8 atm       

  E)     3.3 atm

  c
• 1.         At STP, how many moles of helium would occupy 1.00 L?     

  A)    224 moles

  B)     22.4 moles

  C)    0.0446 moles

  D)    0.446 moles

  E)     2.24 moles

   

  c
• 1.         A sample of gas initially has a volume of 468 mL at 318 K and 2.90 atm. What pressure will the sample have if the volume changes to 341 mL while the temperature is increased to 522 K?

  A)    10.2 atm

  B)     9.83 atm

  C)    15.3 atm

  D)    6.53 atm

  E)     1.05 atm

  d
• 1.         To what temperature must a balloon, initially at 19°C and 1.50 L, be heated in order to have a volume of 5.10 L?

  A)    993 K

  B)     403 K

  C)    75 K

  D)    655 K

  E)     894 K

  a
• 1.         What is the new volume of a balloon originally at 755 torr and 5.00 L is placed in a container in which the pressure is increased to 950 atm?      

  A)    6.29 L         

  B)     5.23 × 10-3 L            

  C)    39.7 L         

  D)    0.159 L        

  E)     302 L

  b
• 1.          If a sample of 0.29 moles of Ar occupies 3.8 L under certain conditions, what volume will 0.66 moles occupy under the same conditions?

  A)    12 L

  B)     8.6 L

  C)    17 L

  D)    5.0 L

  E)     15 L

   

  b
• 1.          If a sample of 0.29 moles of Ar occupies 3.8 L under certain conditions, what volume will 0.66 moles occupy under the same conditions?

  A)    12 L

  B)     8.6 L

  C)    17 L

  D)    5.0 L

  E)     15 L

   

  d
• 1.         What is the rms speed (m/s) of  N2 at  33.5 °C?          

  1. 522          B) 173        C) 51.9        D) 16.5         E) 302

   

  a
•  

  1.         A sample of N2 effuses in  220 s. How long will the same size sample of Cl2 take to effuse?     

  1. 558 s          B) 388 s     C) 350 s                  D) 86.8 s         E) 138 s

   

  e
• 1.         A mixture of N2,  O2 and  He have mole fractions of 0.25, 0.65, and 0.10, respectively. What is the pressure of N2 if the total pressure of the mixture is 3.9 atm?           

   

  1. 0.67 atm       B) 2.5 atm         C) 1.33 atm       D) 0.98 atm       E) 0.39 atm

  d
• 1.         A gas mixture consists of N2, O2, and Ne, where the mole fraction of N2 is 0.55 and the mole fraction of Ne is 0.25. If the mixture is at STP in a 5.0 L container, how many molecules of O2 are present?    

   

  1. 3.7 × 1023 molecules O2

  B) 9.3 × 1024 molecules O2

  C) 2.7 × 1022 molecules O2

  D) 4.5 × 1022 molecules O2

  E) 1.1 × 1023 molecules O2

  c
•  

  1.         Which is expected to have the largest dispersion forces? 

  1. Be Cl2          B) C12H26        C) F2    D) C3H8

  b
•        Choose the substance with the highest boiling point.

  1. K I   B) CH4 C) I2     D) CS2  E) HF

   

  a
• 1.         Which of the following substances would you predict to have the highest melting point?

  1. CH2CH2OH

  B) HCl

  C) CH3CH3

  D) CH3Cl

  E) CH3CH2CH2CH3

  a
•  

   

  1.         Apply the like dissolves like rule to predict which of the following liquids is not soluble with hexane, C6H14.     

   

  1. carbon tetrachloride, CCl4

  B) water, H2O

  C) toluene, C6H5CH3 

  D) all of the above

  E) none of the above

   

  b
• Reduction


  The gain of electrons by a species in a redox reaction, resulting in a decrease in oxidation state.
• Oxidation


  The loss of electrons by a species in a redox reaction, resulting in an increase in oxidation state.
• Redox Reaction


  A chemical reaction that involves a transfer of electrons from one species to another, resulting in a change in oxidation state.
• ΔT = Q / (m \* c)

  Formula used to calculate temperature change, where ΔT is the temperature change, Q is the heat gained, m is the mass, and c is the specific heat capacity.
• Heat required formula

  q = mcΔT
• 1 (cal)=4.184(J)
• 1(kcal)=1000 (cal)
• 1 (Cal)=1kcal or 1000cal