Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
21 Cards in this Set
- Front
- Back
|
Thermodynamics can be used to determine all of the following EXCEPT |
the rate of reaction |
|
|
Which of the following statements concerning entropy is/are CORRECT?1. The entropy of a substance increases when converted from a liquid to a solid.2. The entropy of a substance decreases as its temperature increases.3. All substances have positive entropy values at temperatures above 0 K. |
3 only |
|
|
In the lab, you mix two solutions (each originally at the same temperature) and the temperature of the resulting solution decreases. Which of the following is true? |
The chemical reaction is absorbing energy and is endothermic. |
|
|
Diluting concentrated sulfuric acid with water can be dangerous. The temperature of the solution can increase rapidly. What are the signs of ΔH, ΔS, and ΔG for this process? |
ΔH < 0, ΔS > 0, ΔG < 0 |
|
|
Which response includes all of the following processes that are accompanied by an increase in entropy? |
1, 3 |
|
|
Calculate the standard entropy change for the following reaction: 2 SO2(g) + O2(g) à 2 SO3(g)given S°[SO2(g)] = 248.2 J/Kmol, S° [O2(g)] = 205.1 J/Kmol-, and S° [SO3(g)] = 256.8 J/Kmol-. |
–187.9 J/K |
|
|
The reaction rates of many spontaneous reactions are actually very slow. Which of these statements is the best explanation for this observation? |
The activation energy of the reaction is large. |
|
|
Determine G° for the following reaction: CH4(g) + O2(g) à CO2(g) + 2 H2O(g)given DfG° [CH4(g)] = –50.7 kJ/mol, DfG° [H2O((g)] = –237.4 kJ/mol, DfG° [O2(g)] = 0.0 kJ/mol, and DfG° [CO2(g)] = –394.4 J/mol. |
818.5 kJ |
|
|
Sodium carbonate can be made by heating sodium bicarbonate: 2 NaHCO3(s) ® Na2CO3(s) + CO2(g) + H2O(g) Given that DHo = 128.9 kJ/mol and DSo = 321.0 J/K at 25oC, above what minimum temperature will the reaction become spontaneous under standard state conditions? |
128.9°C |
|
|
Which of these species has the highest entropy (So) at 25oC? |
CH4(g) |
|
|
All of the following processes lead to an increase in entropy EXCEPT |
decreasing the volume of a gas |
|
|
Calculate the standard entropy change for the combustion of ethanol at 25°C. CH3CH2OH() + 3 O2(g) à 2 CO2(g) + 3 H2O(g)Species S° (J/K mol)CH3CH2OH() 160.7O2(g) 205.1CO2(g) 213.7H2O(g) 188.8 |
+217.8 J/K |
|
|
The DrG° for the following reaction is –100.4 kJ: C2H4(g) + H2(g) à C2H6(g)Given DfG° [C2H4(g)] = +68.4 kJ/mol, calculate DfG° [C2H6(g)]. |
–32.0 kJ/mol |
|
|
If a cube of ice at 0oC is placed outside on a warm summer day, the ice will melt spontaneously. What are the signs of ΔH, ΔS, and ΔG for this process? |
ΔH > 0, ΔS > 0, ΔG < 0 |
|
|
Which of the following statements concerning entropy is/are CORRECT?1. The entropy of a substance increases when converted from a liquid to a solid.2. The entropy of a substance decreases as its temperature increases.3. All substances have positive entropy values at temperatures above 0 K. |
3 only |
|
|
Which of these species has the highest entropy at 25oC? |
CO(g) |
|
|
Without reference to a table, arrange these reactions according to increasing DS. |
2 < 3 < 1 |
|
|
For a particular chemical reaction∆H = 5.5 kJ and ∆S = -25J/KUnder what temperature condition is the reaction spontaneous? |
Not at any temperature |
|
|
Which of the following linear chain alcohols is likely to have the highest standard entropy in the liquid state? |
CH3CH2CH2CH2CH2OH |
|
|
Which of the following statements is/are CORRECT?1. Spontaneous changes only occur in the direction that leads to equilibrium.2. Exothermic reactions are always spontaneous.3. In any chemical reaction, energy must be conserved. |
1 and 3 |
|
|
Which of the following processes is/are endothermic?1. the combustion of hydrogen 2. the condensation of water 3. the evaporation of isopropyl alcohol |
3 only |
