Rates and Orders

The rate equation for the hydrogenation of ethene is Rate = k[C₂H₄][H₂]
At a fixed temperature, the reaction mixture is compressed to triple the original pressure. What is the factor by which the rate of reaction changes?

• 6
• 9
• 12
• 27

The graph shows a typical energy distribution for particles of an ideal gas in a sealed container at a fixed temperature.   Which of the following statements is true?

• Position A represents the mean energy of a molecule in the container.
• Addition of a catalyst moves the position of E_A to the right.
• The area under the curve to the right of E_A represents the number of molecules with enough energy to react.
• The position of the peak of the curve at a higher temperature is further away from both axes.

Tags

NGSS.HS-PS1-5

NGSS.HS-PS3-4

In the reaction between propanone and ethane-1,2-diol, a mixture of 1.00 g of propanone, 5.00 g of ethane-1,2-diol and 0.100 g of benzenesulphonic acid, C₆H₅SO₃H, is heated under reflux in an inert solvent. Benzenesulphonic acid is a strong acid. When the concentration of benzenesulphonic acid is doubled, the rate of the reaction doubles. It can be deduced that

• the reaction is first order overall.
• the reaction is acid-catalysed.
• the reaction is third order overall
• units for the rate constant, k, are mol⁻² dm⁶ s⁻¹.

In the Maxwell-Boltzmann distribution shown, which letter best represents the mean energy of the molecules?

• A
• B
• C
• D

The equation and rate law for the reaction of substance P with substance Q are given below:
2P + Q → R + S
 rate = k[P]²[H⁺]
Under which one of the following conditions, all at the same temperature, would the rate of reaction be slowest?

• [P] 3  pH 3
• [P] 0.1  pH 0
• [P] 1  pH 2
• [P] 10  pH 4

Rate = k [A]² [B] 
What are the correct units for the rate constant in the rate equation above?

• mol dm⁻³ s⁻¹
• mol⁻¹ dm⁻³ s⁻¹
• mol² dm⁻⁶ s⁻¹
• mol⁻² dm⁶ s⁻¹

Which experiments would be used to measure the rate order for A?

• trials 1 and 2
• trials 1 and 3
• trials 2 and 3

What is the order of reaction with respect to  A?

• 0
• 1
• 2

What is the order of reaction with respect to B?

• 0
• 1
• 2

Which is the rate determining step?

• 1
• 2
• 3