quiz代考_化学quiz代考 Chemistry Midterm 3 Au19

Midterm 3 Au19

化学quiz代考 A very large equilibrium constant (ex: 1030) indicates that the reaction proceeds until it is essentially all productsA large

1. Which of the following statements is true regarding the kinetic molecular theory of gases?


2. i) The actual volume of gas molecules is negligible compared to the space they occupy.


3. ii) The attractive forces among particles of a gas are negligible

iii) The average kinetic energy of gas molecules is proportional to the temperature, expressed in Kelvin

1. iv) Given that there is no chemical reactions between gases, the ability to mix the gases in a rigid container of fixed volume depends on the external atmospheric pressure.


2. v) Particles interact with one another and with the container walls with loss of total kinetic energy


3. i, and ii


4. i, ii and iii


5. i, ii, iii, and iv


6. i, iii, iv and v


7. i, ii, iii, iv and v

2. 
   

   A gas occupies 250. mL at 700. Torr and 300. K. What volume (mL) will the gas occupy at 350. Torr and 450. K?  化学quiz代考

   
   

750. 750.


751. 83.3


752. 375


753. 500.


754. 950.

3. 
   

   A balloon is filled to 5.60 liters in a store at 20^oC and then is taken outside where the temperature is 38^oC. What is the resulting volume (L) of the balloon?

   
   

5. 5.25


6. 6.18


7. 5.80


8. 5.94


9. 
   

   6.28

   
   

4. 
   

   Which of the following relationships gives a straight line with a positive slope when graphed?  化学quiz代考

   
   

1. V vs T (constant P and amount (n))


2. P vs. V (constant amount (n) and Temperature)

iii. P vs. T (constant V and amount (n))

1. i and ii only


2. ii and iii only


3. i and iii only


4. i, ii, and iii

5. 
   

   Of the following substances, only _________ has London dispersion forces as its only intermolecular force.  化学quiz代考

   
   


6. H₂O


7. CCl₄


8. HF


9. CH₃COOH


10. NH3

6. 
   

   Which of the following substances can form intermolecular hydrogen bonds in the pure liquid?

   
   

1. 1, 2 and 3


2. 2 only


3. 1 and 3 only


4. 2 and 3 only

7. 
   

   Vapor pressure can be described as  化学quiz代考

   
   

1. The temperature at which bubbles of vapor appear in a liquid


2. The pressure exerted on the earth by the particles in the air


3. The temperature at which the vapor pressure of a liquid equals atmospheric pressure


4. The pressure exerted by a gas above the surface of its liquid


5. The pressure within the lungs during inhalation

8. 
   

   The following trend can be best explained by which type of intermolecular forces?

   
   

Element      Boiling Point

He                        4 K

Ne                       25K

Ar                        95K

Kr                       125 K

Xe                      170K

1. London dispersion forces


2. dipole forces


3. hydrogen bonding


4. the octet rule

9. 
   

   Which of the following compounds has the highest boiling point? 化学quiz代考

   
   

1. Heptane


2. 2-methylhexane


3. 2,3-dimethylpentane


4. pentane

10. 
    

    Water is a polar solvent and hexane (C₆H₁₄) is a nonpolar solvent. Which of the following correctly describes the solubility of the solute?

    
    

1. Mineral oil, soluble in water


2. CaCl₂, soluble in hexane


3. Na₂CO₃, soluble in water


4. CCl₄, soluble in water


5. Octane (C₈H₁₈), soluble in water

11. 
    

    Which of the following types of lipids is predominantly found in cell membranes?

    
    

1. Waxes II. Cholesterol III. Phospholipids   IV. Triglycerides

1. I


2. II


3. III


4. II and III


5. IV

12. 
    

    An increase in the temperature of a solution usually

    
    

1. Increases the boiling point


2. Increases the solubility of a gas in the solution


3. Increases the solubility of a solid solute in the solution


4. Decreases the solubility of a solid solute in the solution


5. Decreases the solubility of a liquid solute in the solution

13. 
    

    When the weak electrolyte HF is dissolved in water, the solution contains ______________.  化学quiz代考

    
    

1. All HF molecules


2. All H+ and F- ions and no HF molecules


3. Nothing


4. Mostly HF molecules and a few H+ and F- ions


5. Only F- ions

14. 
    

    What is the molarity of a solution that contains 2.35 g of NH₃ in 0.0500 L of solution?

    
    

27. 27.6 M


28. 2.76 M


29. 47.0 M


30. 0.276 M


31. 1.00 M

15. 
    

    How many grams of glucose are needed to prepare 400. g of a 2.00% (m/m) glucose solution?

    
    

800. 800. g


801. 0.00500 g


802. 8.00 g


803. 2.00 g


804. 200. g

16. 
    

    What is the lead concentration in ppb of a water sample that contains 28 mg of lead in 44L?

    
    

1. 0.064 ppb


2. 0.64 ppb


3. 64 ppb


4. 640 ppb

17. 
    

    What volume (mL) of 3.29 M (NH₄)₂SO₄ should be used to prepare 100.0 mL of a 0.20M solution?  化学quiz代考

    
    

7. 7.2


8. 5.6


9. 6.9


10. 6.1


11. 6.5

18. 
    

    The transport of nitrogen molecules across a cell membrane occurs via:

    
    

1. passive diffusion


2. facilitated transport


3. active transport

19. 
    

    Which of the following does not represent a conjugate acid-base pair?

    
    

1. A) HCO3-/CO32-


2. B) H3PO4/HPO42-


3. C) OH-/O2-


4. 
   

   D) NH4+/NH3

   
   

20. 
    

    Which of the following is not capable of acting like a Bronsted-Lowry base?  化学quiz代考

    
    

1. H₂0 (l)


2. NH₄⁺ ion


3. Cl^- ion


4. H₂PO₄^- (aq)

21. Calculate the value of the equilibrium constant for the following reaction at 1200 K:

CO (g)  +  3 H₂ (g)  Û CH₄ (g)  +  H₂O (g)

If the concentration of the species at equilibrium at 1200 K are:

[CO] = 0.0613 M, [H₂] = 0.184 M, [CH₄] = 0.0387 M, [H₂O] = 0.0387 M

1. 0.255


2. 0.133


3. 7.53


4. 0.722


5. 3.92

22. 
    

    Consider equilibrium constants. Which of the following is FALSE?

    
    

1. A very large equilibrium constant (ex: 10³⁰) indicates that the reaction proceeds until it is essentially all products


2. A large equilibrium constant (ex: 4000) indicates that at equilibrium, there are more products than reactants


3. A small equilibrium constant (ex: 0.000005) indicates that at equilibrium there are more reactants than products


4. An equilibrium constant of approximately 1 indicates that the equilibrium mixture is essentially all reactants


5. The presence of a catalyst does not affect the value of the equilibrium constant

23. 
    

    The following reaction is exothermic. Which of the following change at equilibrium will drive the reaction to the right (toward products)  化学quiz代考

    
    

CH₄ (g)  + 2 O₂ (g)  Û  CO₂ (g)  +  2 H₂0 (g)

1. A decrease in temperature and addition of CO₂


2. A decrease in temperature and addition of CH₄


3. An increase in temperature and addition of H₂O


4. An increase in temperature and addition of O₂

24. 
    

    Which one of the following is the weakest acid?

    
    

6. HCN (Ka = 6.3 x 10^-10)


7. HClO (Ka = 3.0 x 10^-8)


8. HNO₂ (Ka = 4.5 x 10^-4)


9. HF (Ka = 6.5 x 10^-4)

25. 
    

    What is the [H₃O⁺} concentration of a solution that has a pH = 2.34?  化学quiz代考

    
    

2. 2.3 x 10^-3 M


3. 4.6 x 10^-3 M


4. 2.2 x 10^-12M


5. 1.2 x 10¹ M

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