Thermo
Thermo II
Reaction Rates
Equilibrium
Free Energy
100
A reaction that releases heat
Exothermic
100
The amount of heat needed to increase the temperature by exactly 1°C
Heat capacity
100
What are the 4 factors that affect reaction rate?
Temperature, concentration, particle size, catalyst
100
At equilibrium, what is the same for both directions of a reaction?
Rate
100
The energy in a chemical reaction that is available to do work
Free energy
200
The reaction below has a change in enthalpy of -26.3 kJ. How much heat does this reaction release if only 1.5 mol of carbon dioxide is produced?
Fe₂O₃ + 3CO → 2Fe + 3CO₂
13.15 kJ
200
By dissolving 3 g of KOH in water, the solution released 4.741 kJ of heat. What is the molar enthalpy of solution of KOH?
-88.6 kJ/mol
200
2SO2(g) + O2(g) ⇋ 2SO3(g)
In the reaction above, when the concentration of oxygen is increased from 0.002 to 0.004, the reaction rate goes from 2.5 x 10-6 to 1.0 x 10-5. What is the order of oxygen gas?
Second order
200
AgBr has a Ksp of 7.7 x 10-13, and AgCl has a Ksp value of 1.6 x 10-10. Which of the two compounds is more soluble in water?
AgCl
200
If a reaction is endothermic and has a loss in entropy. How would you describe the spontaneity of this reaction?
Nonspontaneous at all temperatures
300
A 150 g sample of water is heated from 25.0°C to 45.0°C. If the specific heat capacity of water is 4.18 J/g°C, how much heat energy is absorbed?
12,540 J
300
How much heat is released when 150.0 g of liquid water at 0°C freezes into ice?
Water's molar heat of solidification is -6.01 kJ/mol
50.1 kJ
300
Rate = k[NO]2[Cl2]
300
List 3 changes would lead to an equilibrium position favoring the product side.
(ex)
Increase in pressure, Removal of ammonia, Addition of hydrogen gas
300
Determine the ΔS of the following reaction using the given standard entropy values (J/mol) given below:
C3H8 (g)+ 5O2 (g) —> 3CO2 (g) + 4H2O (g)
C₃H₈(g) = 269.9, O₂(g) = 205.0, CO₂(g) = 213.7, H₂O(g) = 188.8
101.4 J/mol
400
A 50.0 g sample of an unknown liquid cools from 35.0°C to 20.0°C, releasing 7,500 J of heat. What is the specific heat of the liquid?
-10.0 J/g°C
400
CH4(g) + 2O2(g)→CO2(g) + 2H2O(l)
CH₄(g) = –74.8 kJ/mol
CO₂(g) = –393.5 kJ/mol
H₂O(l) = –285.8 kJ/mol
Calculate the standard enthalpy change (ΔH°rxn) for the combustion of methane:
-890.3 kJ
400
NO + O₃ → NO₂ + O₂ has the following rate law:
Rate = k[NO][O₃]
If the k is 0.05 and [NO] = 0.040 M and [O₃] = 0.040 M, what is the rate?
8 x 10-5 M/s
400
2SO2(g) + O2(g) ⇋ 2SO3(g)
Determine the equilibrium expression of the reaction.
[SO3]2/[SO2]2[O2]
400
SO2(g) + 1/2 O2(g) --> SO3(g)
The synthesis of sulfur trioxide above releases heat.
Determine the signs of ΔH and ΔS of this reaction.
-ΔH,-ΔS
500
What is the standard change in enthalpy of C(s) + O₂(g) → CO₂(g)
Given:
C(s) + ½ O₂(g) → CO(g) ΔH = –110.5 kJ
CO(g) + ½ O₂(g) → CO₂(g) ΔH = –283.0 kJ
-393.5 kJ
500
How much heat is needed to melt a 25 g ice cube at -10°C completely into water at 0°C.
Specific heat of ice = 2.09 J/g°C
Heat of fusion of water = 334 J/g
8872.5 J or 8.9 kJ
500
2.7 x 10-4
500
N₂(g) + 3H₂(g) ⇌ 2NH₃(g)
The equilibrium concentrations are measured to be:
[N₂] = 0.40 M, [H₂] = 0.60 M, [NH₃] = 0.80 M
Calculate the equilibrium constant for this reaction.
7.41
500
2NO2(g)→N2O4(g)
The standard enthalpy change (ΔH°) for this reaction is –57.2 kJ/mol, and the standard entropy change (ΔS°) is –175.8 J/mol·K.
Calculate the standard Gibbs free energy change (ΔG°) for the reaction at 25°C, and describe the spontaneity of the reaction.
–4.81kJ/mol; spontaneous only at low temperatures