Reaction Rates
0.014
A flask is charged with 0.124 mol of A and allowed to react to form B according to the reaction A(g) →B(g). The following data are obtained for [A] as the reaction proceeds: Time (s) 0.00 - 10.0 - 20.0 - 30.0 - 40.0 Moles A 0.124 - 0.110 - 0.088 - 0.073 - 0.054 How many moles of B are present at 10 s? A) 0.011 B) 0.220 C) 0.110 D) 0.014 E) 1.4 × 10⁻³
0.051
A flask is charged with 0.124 mol of A and allowed to react to form B according to the reaction A(g) →B(g). The following data are obtained for [A] as the reaction proceeds: Time (s) 0.00 - 10.0 - 20.0 - 30.0 - 40.0 Moles A 0.124 - 0.110 - 0.088 - 0.073 - 0.054 How many moles of B are present at 30 s? A) 2.4 × 10⁻³ B) 0.15 C) 0.073 D) 1.7 × 10⁻³ E) 0.051
1.5 × 10⁻³
A flask is charged with 0.124 mol of A and allowed to react to form B according to the reaction A(g) →B(g). The following data are obtained for [A] as the reaction proceeds: Time (s) 0.00 - 10.0 - 20.0 - 30.0 - 40.0 Moles A 0.124 - 0.110 - 0.088 - 0.073 - 0.054 The average rate disappearance of A between 20 s and 30 s is ________ mol/s. A) 5.0 × 10⁻⁴ B) 1.6 × 10⁻² C) 1.5 × 10⁻³ D) 670 E) 0.15
+1.5 × 10⁻³
A flask is charged with 0.124 mol of A and allowed to react to form B according to the reaction A(g) →B(g). The following data are obtained for [A] as the reaction proceeds: Time (s) 0.00 - 10.0 - 20.0 - 30.0 - 40.0 Moles A 0.124 - 0.110 - 0.088 - 0.073 - 0.054 The average rate of appearance of B between 20 s and 30 s is ________ mol/s. A) +1.5 × 10⁻³ B) +5.0 × 10⁻⁴ C) -1.5 × 10⁻³ D) +7.3 × 10⁻³ E) -7.3 × 10⁻³
1.7 × 10⁻³
A flask is charged with 0.124 mol of A and allowed to react to form B according to the reaction A(g) →B(g). The following data are obtained for [A] as the reaction proceeds: Time (s) 0.00 - 10.0 - 20.0 - 30.0 - 40.0 Moles A 0.124 - 0.110 - 0.088 - 0.073 - 0.054 The average rate of disappearance of A between 20 s and 40 s is ________ mol/s. A) 8.5 × 10⁻⁴ B) 1.7 × 10⁻³ C) 590 D) 7.1 × 10⁻³ E) 1.4 × 10⁻³
2.2 × 10⁻³
A flask is charged with 0.124 mol of A and allowed to react to form B according to the reaction A(g) →B(g). The following data are obtained for [A] as the reaction proceeds: Time (s) 0.00 - 10.0 - 20.0 - 30.0 - 40.0 Moles A 0.124 - 0.110 - 0.088 - 0.073 - 0.054 The average rate of disappearance of A between 10 s and 20 s is ________ mol/s. A) 2.2 × 10⁻³ B) 1.1 × 10⁻³ C) 4.4 × 10⁻³ D) 454 E) 9.90 × 10⁻³
2.8 × 10⁻⁴
At elevated temperatures, dinitrogen pentoxide decomposes to nitrogen dioxide and oxygen: 2N₂O₅(g) → 4NO₂ (g) + O₂ (g) When the rate of formation of NO₂ is 5.5 × 10⁻⁴ M/s, the rate of decomposition of N₂O₅ is ________ M/s. A) 2.2 × 10⁻³ B) 1.4 × 10⁻⁴ C) 10.1 × 10⁻⁴ D) 2.8 × 10⁻⁴ E) 5.5 × 10⁻⁴
7.2 × 10⁻³
At elevated temperatures, dinitrogen pentoxide decomposes to nitrogen dioxide and oxygen: 2N₂O₅(g) → 4NO₂ (g) + O₂ (g) When the rate of formation of O₂ is 2.2 × 10⁻⁴ M/s, the rate of decomposition of N₂O₅ is ________ M/s. A) 7.2 × 10⁻³ B) 3.6 × 10⁻³ C) 1.8 × 10⁻³ D) 1.4 × 10⁻² E) 0.00090
0.079
At elevated temperatures, methylisonitrile (CH₃NC) isomerizes to acetonitrile (CH₃CN): CH₃NC (g) → CH₃CN (g) At the start of an experiment, there are 0.200 mol of reactant and 0 mol of product in the reaction vessel. After 25 min, 0.121 mol of reactant (CH₃NC) remain. There are ________ mol of product (CH₃CN) in the reaction vessel. A) 0.022 B) 0.121 C) 0.200 D) 0.321 E) 0.079
3.7 × 10⁻³
At elevated temperatures, methylisonitrile (CH₃NC) isomerizes to acetonitrile (CH₃CN): CH₃NC (g) → CH₃CN (g) At the start of the experiment, there are 0.200 mol of reactant (CH₃NC) and 0 mol of product (CH₃CN) in the reaction vessel. After 25 min of reaction, 0.108 mol of reactant (CH₃NC) remain. The average rate of decomposition of methyl isonitrile, CH₃NC, in this 25 min period is ________ mol/min. A) 3.7 × 10⁻³ B) 0.092 C) 2.3 D) 4.3 × 10⁻³ E) 0.54
+2/3
Consider the following reaction: 3A → 2B The average rate of appearance of B is given by Δ[B]/Δt. Comparing the rate of appearance of B and the rate of disappearance of A, we get Δ[B]/Δt = ________ × (-Δ[A]/Δt). A) -2/3 B) +2/3 C) -3/2 D) +1 E) +3/2
+2
Consider the following reaction: A → 2C The average rate of appearance of C is given by Δ[C]/Δt. Comparing the rate of appearance of C and the rate of disappearance of A, we get Δ[C]/Δt = ________ × (-Δ[A]/Δt). A) +2 B) -1 C) +1 D) +1/2 E) -1/2
1.0 × 10⁻⁵
Nitrogen dioxide decomposes to nitric oxide and oxygen via the reaction: 2NO₂ (g) → 2NO (g) + O₂ (g) In a particular experiment at 300 °C, [NO₂] drops from 0.0100 to 0.00800 M in 100 s. The rate of appearance of O₂ for this period is ________ M/s. A) 1.0 × 10⁻⁵ B) 2.0 × 10⁻⁵ C) 4.0 × 10⁻⁵ D) 2.0 × 10⁻³ E) 4.0 × 10⁻³
2.79 × 10⁻⁵
Nitrogen dioxide decomposes to nitric oxide and oxygen via the reaction: 2NO₂ → 2NO + O₂ In a particular experiment at 300 °C, [NO₂] drops from 0.0143 to 0.00701 M in 261 s. The rate of disappearance of NO₂ for this period is ________ M/s. A) 2.79 × 10⁻⁵ B) -8.16 × 10⁻⁵ C) 5.59 × 10⁻⁵ D) 1.40 × 10⁻⁵ E) 35,800
mol/L
Of the following, all are valid units for a reaction rate except: A) mol/L B) M/s C) mol/hr D) g/s E) mol/L⁻hr
M⁻² s⁻¹
Of the units below, ________ are appropriate for a third-order reaction rate constant. A) M⁻² s⁻¹ B) M s⁻¹ C) s⁻¹ D) M⁻¹ s⁻¹ E) mol/L
0.043
The combustion of ethylene proceeds by the reaction C₂H₄ (g) + 3O₂ (g) → 2CO₂ (g) + 2H₂O (g) When the rate of disappearance of O₂ is 0.13 M s⁻¹, the rate of disappearance of C₂H₄ is ________ M s⁻¹. A) 0.087 B) 0.043 C) 0.39 D) 0.20 E) 0.26
0.087
The combustion of ethylene proceeds by the reaction C₂H₄ (g) + 3O₂ (g) → 2CO₂ (g) + 2H₂O (g) When the rate of disappearance of O₂ is 0.13 M s⁻¹, the rate of appearance of CO₂ is ________ M s⁻¹. A) 0.087 B) 0.043 C) 0.39 D) 0.20 E) 0.26
2.0 × 10⁻⁵
The peroxydisulfate ion (S₂O₈²⁻) reacts with the iodide ion in aqueous solution via the reaction: S₂O₈²⁻ (aq) + 3I⁻ → 2SO₄ (aq) + I₃⁻ (aq) An aqueous solution containing 0.050 M of S₂O₈²⁻ ion and 0.072 M of I⁻ is prepared, and the progress of the reaction followed by measuring [I⁻]. The data obtained is given in the table below. Time (s) 0.000 - 400.0 - 800.0 - 1200.0 - 1600.0 [I⁻] (M) 0.072 - 0.057 - 0.046 - 0.037 - 0.029 The average rate of disappearance of I⁻ between 1200.0 s and 1600.0 s is ________ M/s. A) 1.8 × 10⁻⁵ B) 1.2 × 10⁻⁵ C) 2.0 × 10⁻⁵ D) 5.0 × 10⁴ E) 1.6 × 10⁻⁴
2.8 × 10⁻⁵
The peroxydisulfate ion (S₂O₈²⁻) reacts with the iodide ion in aqueous solution via the reaction: S₂O₈²⁻ (aq) + 3I⁻ → 2SO₄ (aq) + I₃⁻ (aq) An aqueous solution containing 0.050 M of S₂O₈²⁻ ion and 0.072 M of I⁻ is prepared, and the progress of the reaction followed by measuring [I⁻]. The data obtained is given in the table below. Time (s) 0.000 - 400.0 - 800.0 - 1200.0 - 1600.0 [I⁻] (M) 0.072 - 0.057 - 0.046 - 0.037 - 0.029 The average rate of disappearance of I⁻ between 400.0 s and 800.0 s is ________ M/s. A) 2.8 × 10⁻⁵ B) 1.4 × 10⁻⁵ C) 5.8 × 10⁻⁵ D) 3.6 × 10⁴ E) 2.6 × 10⁻⁴
3.8 × 10⁻⁵
The peroxydisulfate ion (S₂O₈²⁻) reacts with the iodide ion in aqueous solution via the reaction: S₂O₈²⁻ (aq) + 3I⁻ → 2SO₄ (aq) + I₃⁻ (aq) An aqueous solution containing 0.050 M of S₂O₈²⁻ ion and 0.072 M of I⁻ is prepared, and the progress of the reaction followed by measuring [I⁻]. The data obtained is given in the table below. Time (s) 0.000 - 400.0 - 800.0 - 1200.0 - 1600.0 [I⁻] (M) 0.072 - 0.057 - 0.046 - 0.037 - 0.029 The average rate of disappearance of I⁻ in the initial 400.0 s is ________ M/s. A) 6.00 B) 3.8 × 10⁻⁵ C) 1.4 × 10⁻⁴ D) 2.7 × 10⁴ E) 3.2 × 10⁻⁴
0.036
The peroxydisulfate ion (S₂O₈²⁻) reacts with the iodide ion in aqueous solution via the reaction: S₂O₈²⁻ (aq) + 3I⁻ → 2SO₄ (aq) + I₃⁻ (aq) An aqueous solution containing 0.050 M of S₂O₈²⁻ ion and 0.072 M of I⁻ is prepared, and the progress of the reaction followed by measuring [I⁻]. The data obtained is given in the table below. Time (s) 0.000 - 400.0 - 800.0 - 1200.0 - 1600.0 [I⁻] (M) 0.072 - 0.057 - 0.046 - 0.037 - 0.029 The concentration of S₂O₈²⁻ remaining at 1600 s is ________ M. A) 0.036 B) 0.014 C) 0.043 D) 0.064 E) 0.029
+0.045
The peroxydisulfate ion (S₂O₈²⁻) reacts with the iodide ion in aqueous solution via the reaction: S₂O₈²⁻ (aq) + 3I⁻ → 2SO₄ (aq) + I₃⁻ (aq) An aqueous solution containing 0.050 M of S₂O₈²⁻ ion and 0.072 M of I⁻ is prepared, and the progress of the reaction followed by measuring [I⁻]. The data obtained is given in the table below. Time (s) 0.000 - 400.0 - 800.0 - 1200.0 - 1600.0 [I⁻] (M) 0.072 - 0.057 - 0.046 - 0.037 - 0.029 The concentration of S₂O₈²⁻ remaining at 400 s is ________ M. A) +0.015 B) +0.035 C) -0.007 D) +0.045 E) +0.057
0.041
The peroxydisulfate ion (S₂O₈²⁻) reacts with the iodide ion in aqueous solution via the reaction: S₂O₈²⁻ (aq) + 3I⁻ → 2SO₄ (aq) + I₃⁻ (aq) An aqueous solution containing 0.050 M of S₂O₈²⁻ ion and 0.072 M of I⁻ is prepared, and the progress of the reaction followed by measuring [I⁻]. The data obtained is given in the table below. Time (s) 0.000 - 400.0 - 800.0 - 1200.0 - 1600.0 [I⁻] (M) 0.072 - 0.057 - 0.046 - 0.037 - 0.029 The concentration of S₂O₈²⁻ remaining at 800 s is ________ M. A) 0.046 B) 0.076 C) 4.00 × 10⁻³ D) 0.015 E) 0.041
0.0700
The rate of disappearance of HBr in the gas phase reaction 2HBr (g) → H₂ (g) + Br₂ (g) is 0.140 M s⁻¹ at 150 °C. The rate of reaction is ________ M s⁻¹. A) 3.57 B) 0.0700 C) 0.0196 D) 0.280 E) 0.0860
0.095
The rate of disappearance of HBr in the gas phase reaction 2HBr (g) → H₂ (g) + Br₂ (g) is 0.190 M s⁻¹ at 150 °C. The rate of appearance of Br₂ is ________ M s⁻¹. A) 2.63 B) 0.095 C) 0.0361 D) 0.380 E) 0.436
Beer's Law
The relationship of absorbed light to the concentration of the substance absorbing the light is governed by ________.
False
True or False Rates of reaction can be positive or negative.
False
True or False The instantaneous rate of a reaction can be read directly from the graph of molarity versus time at any point on the graph.
All of the above are valid expressions of the reaction rate.
Which one of the following is not a valid expression for the rate of the reaction below? 4NH₃ + 7O₂ → 4NO₂ + 6H₂O A) -1/7 (Δ[O₂]/Δt) B) 1/4 (Δ[NO₂]/Δt) C) 1/6 (Δ[H₂O]/Δt) D) -1/4 (Δ[NH₃]/Δt) E) All of the above are valid expressions of the reaction rate.
O₂
Which substance in the reaction below either appears or disappears the fastest? 4NH₃ + 7O₂ → 4NO₂ + 6H₂O A) NH₃ B) O₂ C) NO₂ D) H₂O E) The rates of appearance/disappearance are the same for all of these.
