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Equilibrium Online Test 2

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 

 1. 

A scientist observed changes in the gas pressure of one mole of a gas in a sealed chamber
with a fixed volume. To identify the source of the changes, the scientist should check for
variations in the
a.
air pressure outside the chamber.
c.
temperature of the chamber
b.
molecular formula of the gas
d.
isotopes of the gas
 

 2. 

Which of  the following has the largest atomic radius?
a.
iodine (I)
c.
chlorine (Cl)
b.
magnesium (Mg)
d.
barium (Ba)
 

 3. 

Copper (II) nitrate and sodium hydroxide solutions react in a test tube as shown below.
           Cu(NO3)2 (aq)     +    2NaOH(aq)    ¾¾®      Cu(OH)2 (s)    +      2NaNO3(aq)
If nitric acid is added to the test tube, the amount of solid precipitate decreases.  The best explanation for this is that the acid
a.
reacts with the copper (II) nitrate, pulling the equilibrium to the left.
c.
will dissolve most solids, including sodium nitrate.
b.
dilutes the solution making the precipitate dissolve.
d.
will react with the copper (II) hydroxide to form water and soluble copper (II) nitrate.
 

 4. 

                          H2    +   Cl2   ¾®   2HCl
Which of these describes the rate of this chemical reaction?
a.
an increase in the concentration of HCl and H2 with time
c.
an increase in H2 and Cl2 with time
b.
an increase in the concentration of HCl with time
d.
a decrease in HCl and Cl2 with time
 

 5. 

C6H6     +    Br2     ¾®    C6H5Br    +    HBr
Which of the following changes will cause an increase in the rate of the above reaction?
a.
increasing the concentration of HBr
c.
decreasing the temperature
b.
increasing the concentration of Br2
d.
decreasing the concentration of C6H6
 

 6. 

                   2CO     +     O2     ¾®    2CO2
If the above reaction takes place inside a sealed chamber, then which of these procedures will cause a decrease in the rate of reaction?
a.
removing the CO2 as it is formed
c.
raising the temperature of the reaction chamber 
b.
increasing the volume inside the reaction chamber
d.
adding more CO to the reaction chamber
 

 7. 

A catalyst can speed up the rate of a given chemical reaction by
a.
increasing the pressure of reactants, thus favoring products.
c.
increasing the equilibrium constant in favor of products.
b.
lowering the activation energy required for the reaction to occur.
d.
raising the temperature at which the reaction occurs.  
 

 8. 

Which reaction diagram shows the effect of using the appropriate catalyst in a chemical
reaction?
a.
mc008-1.jpg
c.
mc008-3.jpg
b.
mc008-2.jpg
d.
mc008-4.jpg
 

 9. 

When a reaction is at equilibrium and more reactant is added, which of the following changes is the immediate result?
a.
The forward reaction rate remains the same.
c.
The reverse reaction rate decreases.
b.
The forward reaction rate increases.
d.
The reverse reaction rate remains the same.
 

 10. 

In which of the following reactions involving gases would the forward reaction be favored by an increase in pressure?
a.
AC  Û  A  +  C
c.
A  +  B  Û  AB
b.
A  +  B   Û   C  +  D
d.
2A  +  B  Û C +  2D
 

 11. 

4HCl(g)     +    O2 (g)  Û  2H2O (l)   +    2Cl2 (g)    +    113 kJ
Which action will drive the reaction to the right?
a.
adding water to the system
c.
increasing the system’s pressure
b.
heating the equilibrium mixture
d.
decreasing the oxygen concentration
 

 12. 

NO2(g)     +    CO (g)  Û   NO(g)   +    CO2 (g)   
The reaction shown above occurs inside a closed flask.  What action will shift the reaction to the left?
a.
increasing the NO concentration in the flask  
c.
raising the total pressure inside the flask    
b.
pumping CO gas into the closed flask
d.
venting some CO2 gas from the flask
 

 13. 

      NH4Cl(s)     +    heat  Û    NH3(g)   +    HCl(g)   
What kind of change will shift the reaction above to the right to form more products?
a.
a decrease in total pressure
c.
an increase in the concentration of HCl
b.
a decrease in temperature
d.
an increase in the pressure of NH3
 

 14. 

If the below reaction takes place inside a sealed reaction chamber, then which of these procedures will cause a decrease in the rate of the reaction?
2CO + O2  ®  2CO2
a.
Raising the temperature of the reaction chamber
c.
Removing the CO2 as it is formed
b.
Increasing the volume inside the reaction chamber
d.
Adding more CO to the reaction chamber.
 

 15. 

In a sealed bottle that is half full of water, equilibrium will be attained when water molecules
a.
evaporate and condense at equal rates.
c.
cease to evaporate.
b.
are equal in number for both the liquid and the gas phase.
d.
begin to condense.  
 

 16. 

When methane (CH4) gas is burned (combused) in the presence of oxygen, the following chemical reaction occurs.
      CH4    +    2O2   ¾¾®   CO2    +    2H2O
If 1 mole of methane reacts with 2 moles of oxygen, then
a.
1.2 x 1024 molecules of CO2 and 1.2 x 1024 molecules of H2O are produced.
c.
1.2 x 1024 molecules of CO2 and 6.02 x 1023 molecules of H2O are produced.
b.
6.02 x 1023 molecules of CO2 and 6.02 x 1023 molecules of H2O are produced.
d.
6.02 x 1023 molecules of CO2 and 1.2 x 1024 molecules of H2O are produced.
 

 17. 

Which of these describes the rate of this chemical reaction:
H2 + Cl2 ® 2HCl
a.
an increase in the concentration of HCl and H2
c.
an increase in H2 and Cl2 with time
b.
an increase in the concentration of HCl with time
d.
a decrease in HCl and Cl2 with time
 

 18. 

Which of the following changes will cause an decrease in the rate of the below reaction?
C6H6 + Br2 ® C6H5Br + HBr
a.
increasing the concentration of Br2
c.
increasing the concentration of HBr
b.
decreasing the concentration of C6H6
d.
decreasing the temperature
 

 19. 

Enzymes are made of proteins that are large macromolecules composed of ___________.
a.
nucleotides
c.
lipids
b.
monosaccarides
d.
amino acids
 

 20. 

A catalyst can speed up the rate of a given chemical reaction by __________.
a.
increasing the equilibrium constant in favor of products
c.
raising the temperature at which the reaction occurs
b.
lowering the activation energy required for the reaction to occur
d.
increasing the pressure of the reactants, thus favoring production of products
 



 
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