Gen. Chem. 2 - Section 003 NAU

definitions

100

Measure of disorder of a system or molecular randomness

Entropy

200

ΔG, ∆S, and ΔH all have the same general equation form...

ΔG, ∆S, ΔH = ∑(products) - ∑(reactants)

300

When the forward and reverse reactions are occurring at the same rate

Equilibrium

400

Area of chemistry concerned with the speeds, or rates, at which a chemical reaction occurs

Kinetics

500

A perfectly ordered pure crystalline at zero Kelvin will have zero entropy.

Third Law of Thermodynamics

Entropy

100

What is the most entropic state of matter?

Gas

200

True or False.

Temperature is directly proportional to entropy.

True

300

Which one of the following processes produces a decrease in the entropy of the system?

A) dissolution of solid KCl in water

B) mixing of two gases into one container

C) freezing water to form ice

D) melting ice to form water

E) boiling water to form steam

C

400

What are the units for entropy?

J/K or Joules pre Kelvin

500

A thermodynamic identity that relates entropy and enthalpy.

Gibbs Free Energy

Rate of Reaction

100

Which order of reaction directly affects the rate of reaction?

First Order Reaction

200

True or False: The overall reaction rate is always positive. 

True

300

k = 2.784 x 10^-5 s^-1 . What is the order of reaction. 

1st order

400

The concentration of A at 20 seconds is 0.40 M and at 40 seconds is 0.175 M. Calculate the average rate of reaction. 

A ---> B

0.01125 M/s 

500

In the reaction A + 2 B → 3 C + 4 D, the initial concentration of B was 0.0443 M after 17.3 min the concentration of B was 0.0305 M. What is the average rate of disappearance (M/s) of reactant A?

6.65 x 10^-6 M/s

Kinetics

100

At equilibrium what is Delta G equal to? 

0

200

What is the general form for K, for reaction going to products. 

K = [products]/[reactants]

300

What are the units of k for a 2nd order reaction. 

M^-1s^-1

400

For the following rate law, what is the reaction order?

 rate = k[A][B]²

3rd order

500

For the general reaction, write the rate in terms of C

A + 2B ---> 3C +2D

-1/3 Δ[C]/Δt

Problem Sets

100

Find Delat S for the following reaction:           

2C₂H₆(g) + 7O₂(g) ----> 4CO₂(g) + 6H₂O (l)

C₂H₆ = 229.2 J/mol K

O₂ = 205.2 J/mol K

CO₂ = 213.8 J/mol K

H₂O = 70.0 J/mol K

-619.6 J/mol K

200

Find the change in enthalpy for the following reaction.

P₄O₆ + 2O₂ --> P₄H₁₀ 

using:

P₄ + 3O₂ ---> P₄O₆   H_rxn = -16740.1 kJ/mol

P₄ + 5O₂ ---> P₄H₁₀ H_rxn = -2940.1 kJ/mol

13,800 kJ/mol

300

For the first order reaction A ----> products, if the rate of reaction is = 0.00250 M^-1 s^-1 and [A] = 0.484 M, what is the rate constant K for this reaction? 

5.17 x 10^-3 s^-1

400

find the value of k from data table [go to slides]

rate = k [ClO₂]²[OH^-]

k = 230 M/s

500

Suppose that, at a particular moment during the reaction, CH4 is reacting at the rate of 0.020 M/s. At What rate is CCl₄ being formed?

CH₄ + 4Cl₂ --> CCl₄ + 4 HCl

0.020 M/s