The Collision Theory and Rate of Chemical Reactions

For a chemical reaction to occur, molecules or atoms must collide effectively with the correct orientation and the right amount of energy.

• True

• False

The collision theory proposed that chemical reactions resulted from molecular collisions produces transition state before producing the final product.

• True

• False

Bond-forming processes are classified as endothermic reactions because they absorb energy.

• True

• False

Chemical kinetics is a branch of chemistry that relies heavily on experimental results and observations.

• True

• False

Chemical reactions occur if two reacting molecules collide with one another and the energy of the collision is equal to or greater than the inactivation energy.

• True

• False

The reaction of an organic compound with water is known to be a first-order reaction. Calculate the half-life of the reaction if the rate constant has a value of 1.5x10³ s^-1

• 4.62x10^-4 s

• 4.62x10^-4

• 4.62x100^-4 s

• 4.62x10⁴ s

The reaction of a substance with hydrochloric acid has a rate constant value of 2.0x10^-3 M^-1 s^-1. Based on experimental results, the rate of the reaction depends only on hydrochloric acid. Calculate the half-life of the reaction if the initial concentration of hydrochloric acid is 0.40 M.

• 1250

• 1250 s

• 1350 s

• 1230 s

The reaction of an unknown substance with nitric acid has a half-life of 1.2 seconds. Calculate the rate constant of this zero order reaction if the initial concentration of the unknown substance is 4.0 M.

• 1.67 M

• 1.67 M/m

• 1.69 M/s

• 1.67 M/s

The decomposition of most substances is known to be first order reactions. Write the rate law of the decomposition of dinitrogen pentoxide (N₂O₅)

• rate = k

• rate = [N₂O₅]

• rate = k[N₂O₅]

• rate = k[N₂O₅]²

 Consider the hypothetical reaction of A transforming to B. Express the rate in terms of the disappearance of A.

•  $rate\ =\ -\frac{\Delta\left[A\right]}{\Delta t}$  

•  $rate\ =\ \frac{\Delta\left[A\right]}{\Delta t}$  

•  $rate\ =\ \frac{\Delta\left[A\right]}{\Delta\left[B\right]}$  

•  $rate\ =\ \frac{\left[A\right]}{k}$