Question

QUESTION 1

Compute the typical thermal energy of a water molecule at normal conditions: (k_B T) and compare it to the answer to an earlier problem, where you computed the work needed to lift a molecule by a certain distance. Based on this comparison, the thickness of the Earth's atmosphere is about

	a.	100 km
	b.	10 km
	c.	1000 km
	d.	1 km

QUESTION 2

How much energy is released after an Argon atom moving with speed 3.00 km/sec hits a brick wall and get adsorbed?

QUESTION 3

In the previous problem, what is the value of the collision energy in terms of k_BT, assuming the temperature was 95 ^oF at the time?

QUESTION 4

In equilibrium, the number of molecules moving in one direction is equal, on average, to the number of molecules moving in the opposite direction.

True

False

QUESTION 5

In equilibrium, all directions in space are equivalent in that the speeds of molecules moving in any given direction have the same distribution.

True

False

Answer 1

In Question 1, I need the data of the problem they mention for me to do the comparison.

Question 2: I'm not very sure about this, but I think that you need to use the following equation:

E = 1/2 mv²

The atomic mass of Argon is 39.95 g/mol. However it says that it's one atom so:

1 mol = 6.02x10²³ atoms = 39.95 g so

mass of one atom : 39.95 / 6.02x10²³ = 6.64x10^-26 kg

E = 6.64x10^-26 x (3000)² / 2

E = 2.988x10^-19 J

Question 3:

E = 3/2KbT ----> Kb = 1.381x10^-23 J/K

T = 95 °F

T (°C) = 5x(95 - 32)/9 = 35 °C -----> T (K) = 35 + 273 = 308 K

E = 3/2 x 1.381x10^-23 x 308

E = 6.38x10^-21 J

Question 4:

A Chemical equilibrium is a state in which the rate of the forward reaction equals the rate of the backward reaction. In other words, there is no net change in concentrations of reactants and products. This kind of equilibrium is also called dynamic equilibrium.

According to this definition, if you have a reaction:

aA + bB <------> cC + dD

Kc = [C]^c [D]^d / [A]^a [B]^b

To reach the equilibrium the numbers of particles interacting in the reactants, have to be, in average, the same particles interacting in the products. This way, there could be a equilibrium, where the reactants form the products, and the products form back the reactants. So the answer to this Question would be TRUE.

Question 5:

This is FALSE according to the definition of last asnwer, and according to LeChatelier Principle, there's lots of effects that can affect the equilibrium like Pressure, Change in concentration, Volume, etc. So the direction cannot have the same distribution.