Online Exam - Chem2 | Me.Committee

15 Questions | By Moathajlouni | Last updated: Mar 18, 2022 | Total Attempts: 138

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Online Exam - Chem2 | Me.Committee - Quiz

#لجنة_الهندسة_الميكانيكية #الفريق_الأكاديمي. . . R = 8. 314 J/mol >>>> K =0. 0821 L. Atm/mol. K

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1.

Constants >>> R = 8.314 J/mol >>>> K =0.0821 L.atm/mol.k ... Q1) The equilibrium constant for the following reaction is 5.0 × 10⁸at 25° C , the value of Δ G (KJ/mol) for this reaction is : N2(g) + 3H(g) ⇆ 2NH3(g)
- A.
  
  22
- B.
  
  -4.2
- C.
  
  -25
- D.
  
  -50
2.

Q2) The rate constant (s⁻¹) of a first order that has half life of (225 s) is
- A.
  
  0.693
- B.
  
  3.08 × 10^-3
- C.
  
  1.25
- D.
  
  12.5
3.

Q3) As a temperature of a reaction is increased , the rate of the reaction increases because :
- A.
  
  Reactant molecules collide less frequently
- B.
  
  Activation energy is lowered
- C.
  
  Reactant molecules collide more frequently and with greater energy per collision
- D.
  
  Reactant molecules collide less frequently and with greater energy per collision
4.

Q4) why is potassium bromide (KBr) is insoluble in carbon tetrachloride (CCl4) ?
- A.
  
  Both KBr and (CCl4) are non polar
- B.
  
  Solvent -solvent interaction are strong
- C.
  
  Solute -solvent interaction are strong
- D.
  
  Solute -solvent interaction are weak
5.

Q4) In general , as temperature increases , reaction rate
- A.
  
  Increases , if the reaction is exothermic
- B.
  
  Increases , if the reaction is endothermic
- C.
  
  Increases , regardless whether the reaction is endothermic or exothermic
- D.
  
  Stays the same if the reaction is first order
6.

Q5) For the elementary reaction NO3 + CO → NO2 + CO2 the molecularity and the rate law of the reaction are :
- A.
  
  2, K [NO3] [CO]
- B.
  
  4, K [NO3] [CO] [NO2] [CO2]
- C.
  
  2, K [NO2] [CO2]
- D.
  
  2, K [NO3] [CO] / [NO2] [CO2]
7.

The reaction A(aq) → B(aq) is first order in [A] . A solution is prepared with [A] = 1.22 M . The following data is obtained as the reaction proceeds . The rate constant (s⁻¹) for this reaction is : Time (s) 0.0 6.0 12.0 18.0 [A] (M) 1.22 0.61 0.31 0.15
- A.
  
  0.23
- B.
  
  1.0
- C.
  
  0.17
- D.
  
  0.12
8.

Q8) A compound decomposes by a first-order process . If 25.0% of the compound decomposes in 60.0 minutes , the half-life of the compound is :
- A.
  
  65
- B.
  
  120
- C.
  
  145
- D.
  
  180
9.

Q9) which of the units below are appropriate for a second-order reaction rate constant
- A.
  
  Ms⁻¹
- B.
  
  S⁻¹
- C.
  
  Mol/L
- D.
  
  M⁻¹ s⁻¹
10.

Q10) A certain second order reaction is 60% complete in 25 minutes . calculate the rate constant (K) of this reaction :
- A.
  
  6.0 × 10^-2
- B.
  
  2.7 × 10^-2
- C.
  
  3.3 × 10^-4
- D.
  
  2.1 × 10^-2
11.

Q11) A sealed 1.0 L flask is charged with 0.500 mol of I₂and 0.500 mol of Br2 . An equilibrium reaction ensues : I₂(g)₊Br2 (g) ⇆ 2 IBr (g) when te container contents achieve equilibrium , the flask contains 0.84 mol of IBr . K_eqis:
- A.
  
  11
- B.
  
  4.0
- C.
  
  110
- D.
  
  6.1
12.

Q12) which is true at equilibrium ?
- A.
  
  The limiting reagent has been consumed
- B.
  
  The rates of the forward and reverse reactions are equal
- C.
  
  The rate constants of the forward and reverse reactions are equal
- D.
  
  The value of the equilibrium constant is 1
13.

Q13) Given the following reaction at equilibrium at 450.0° C : CaCO3 (s) ⇆ CaO (s) + CO2 If pCO2 = 0.0160 atm , then Kc =
- A.
  
  0.0160
- B.
  
  0.0821
- C.
  
  7.23
- D.
  
  2.7 × 10^-4
14.

Q14) The following data were obtained for the reaction BF3 + NH3 → F3BNH3 Exp [BF3] [NH3] initial rate 1 0.25 0.25 0.213 2 0.25 0.125 0.1065 3 0.50 0.125 0.1065 the rate law of the reaction is :
- A.
  
  K [NH3]
- B.
  
  K [BF3]
- C.
  
  K [BF3] [NH3]
- D.
  
  K [NH3]^5
15.

Q15) For the previous question , what is the rate when [BF3] =( 0. 10) , [NH3]= 0.50 M ?
- A.
  
  0.426
- B.
  
  0.50
- C.
  
  0.852
- D.
  
  1.0