# Homework 2 (Due 4/8/16)

Name: ______________________________

Section: _____________________________

Student ID#:__________________________

## Q2.1

Calculate the mean free path and the binary number of collisions per liter per second between Ar atoms at 298 K and 1.00 atm. Use 3.62 Å as the collision diameter of the Ar molecules. Assume ideal gas behavior.

## Q2.2

For molecular oxygen at $$56^{o}C$$, calculate the number of collisions a single molecule makes in 1 second and the total number of binary collisions at P=1.0 atm and P=0.25 atm. How does pressure relate to these two quantities? The collision diameter of oxygen is 3.02 A.

## Q1.3

If gas 1 has a molar mass of 72 g/mol and gas 2 has a molar mass of 2 g/mol. How much faster or slower does gas 2 effuse from a small opening than gas 1 at the same temperature?

## Q2.4

Write the rate of reaction in terms of the rate of disappearance of reactant and the rate of formation of products:

1. $$NO_{(g)} + O_{3 (g)} \rightarrow NO_{2(g)} + O_{2(g)}$$
2. $$2C_2H_{6 (g)} + 7O_{2(g)} \rightarrow 4 CO_{2(g)} + 6 H_2O_{(aq)}$$
3. $$H_{2 (g)} + I_{2 (g)} \rightarrow 2HI_{(g)}$$
4. $$4OH_{(g)} + H_2S_{(g)} \rightarrow SO_{2(g)} + 2H_2O_{(aq)} + H_{2(g)}$$

## Q2.5

Determine the value of the rate constant for the (elementary) reaction:

$I_{2(g)} + H_{2 (g)} \rightarrow 2HI_{(aq)}$

If the [I2] = 0.15 M, [H2] = 0.2M, and the rate of reaction is 0.005 M s-1 at 298 K.

## Q2.6

What are the units of the rate constant for a second-order reaction?

## Q2.7

Derive the half-life formula for the 0th, 1st, and 2nd order kinetics.