Podcast
Questions and Answers
What is the significance of using a scientific calculator during the exam?
What is the significance of using a scientific calculator during the exam?
- It allows for complex calculations beyond basic arithmetic. (correct)
- It helps to visualize chemical reactions.
- It is necessary for creating diagrams.
- It is required for graphing functions.
Which statement about the scantron instructions is correct?
Which statement about the scantron instructions is correct?
- Students may leave a question blank if unsure of the answer.
- Only the answers should be recorded on side one of the scantron. (correct)
- Personal scratch paper can be used during the exam.
- Answers must be marked using a pen for clarity.
What does the formula ΔGrxn = ΔHrxn − TΔSrxn represent?
What does the formula ΔGrxn = ΔHrxn − TΔSrxn represent?
- The relationship between pressure and volume in gases.
- The calculation of enthalpy change in a reaction.
- The calculation of free energy change for a chemical reaction. (correct)
- The relationship between heat and work done during a reaction.
What is the appropriate action if a student creates an answer sheet on the back of the exam?
What is the appropriate action if a student creates an answer sheet on the back of the exam?
Which reaction is most likely to result in a decrease in the entropy of the system?
Which reaction is most likely to result in a decrease in the entropy of the system?
What should a student do if they require a formula reference during the exam?
What should a student do if they require a formula reference during the exam?
What does the equation K_eq = exp(-ΔG°/RT) signify in chemical thermodynamics?
What does the equation K_eq = exp(-ΔG°/RT) signify in chemical thermodynamics?
Which of the following is NOT allowed during the exam according to the guidelines?
Which of the following is NOT allowed during the exam according to the guidelines?
What is the Ksp of BaSO4 at the given temperature?
What is the Ksp of BaSO4 at the given temperature?
Calculate the value of ΔGrxn at a temperature of 700 K given ΔHorxn = 114.44 kJ/mol and ΔSorxn = 128.18 J/mol-K.
Calculate the value of ΔGrxn at a temperature of 700 K given ΔHorxn = 114.44 kJ/mol and ΔSorxn = 128.18 J/mol-K.
Given the partial pressures, what is the ∆G for the reaction P2 (g) + 3 Cl2 (g) ⇋ 2 PCl3 (g) at 298 K?
Given the partial pressures, what is the ∆G for the reaction P2 (g) + 3 Cl2 (g) ⇋ 2 PCl3 (g) at 298 K?
What is the heat of reaction, ΔHorxn, for the combustion of a mole of phenol when the temperature of the calorimeter increases from 23.54°C to 37.86°C?
What is the heat of reaction, ΔHorxn, for the combustion of a mole of phenol when the temperature of the calorimeter increases from 23.54°C to 37.86°C?
Which of the following salts will be least soluble in water, resulting in the lowest concentration of [Ag+]?
Which of the following salts will be least soluble in water, resulting in the lowest concentration of [Ag+]?
If the molar mass of phenol is 94.11 g/mol, what is the heat released upon combustion by burning 3 moles in the calorimeter?
If the molar mass of phenol is 94.11 g/mol, what is the heat released upon combustion by burning 3 moles in the calorimeter?
What is the enthalpy change ΔHorxn for the reaction if ΔGrxn is known to be –200 kJ/mol and ΔSorxn is 50 J/mol-K at 298 K?
What is the enthalpy change ΔHorxn for the reaction if ΔGrxn is known to be –200 kJ/mol and ΔSorxn is 50 J/mol-K at 298 K?
What will be the effect on ΔGrxn if the temperature is increased for a reaction that is endothermic?
What will be the effect on ΔGrxn if the temperature is increased for a reaction that is endothermic?
Which compound will NOT have ∆Hof = 0 kJ/mol?
Which compound will NOT have ∆Hof = 0 kJ/mol?
Calculate ΔH in kJ/mol of NaOH when 8.00 g of NaOH is dissolved in 150.0 g of water, raising the temperature from 25.00°C to 85.00°C. The specific heat of water is 4.184 J/g·°C and the molar mass of NaOH is 40.00 g/mol.
Calculate ΔH in kJ/mol of NaOH when 8.00 g of NaOH is dissolved in 150.0 g of water, raising the temperature from 25.00°C to 85.00°C. The specific heat of water is 4.184 J/g·°C and the molar mass of NaOH is 40.00 g/mol.
How much work (in kJ) is done when a gas expands from a volume of 20.0 L to 50.0 L against a constant pressure of 3.00 atm?
How much work (in kJ) is done when a gas expands from a volume of 20.0 L to 50.0 L against a constant pressure of 3.00 atm?
If 10.0 g of CaC2 reacts with water and releases heat at ΔHof of –150.0 kJ/mol, how much heat is released by the reaction?
If 10.0 g of CaC2 reacts with water and releases heat at ΔHof of –150.0 kJ/mol, how much heat is released by the reaction?
Which process describes a change that is dependent on the path taken?
Which process describes a change that is dependent on the path taken?
How much heat is needed to raise the temperature of 6.00 kg of aluminum from 200.0°C to 700.0°C? The specific heat of aluminum is 0.90 J/g·°C.
How much heat is needed to raise the temperature of 6.00 kg of aluminum from 200.0°C to 700.0°C? The specific heat of aluminum is 0.90 J/g·°C.
What is the enthalpy of fusion for mercury (Hg), given that its normal freezing point is –38.9°C?
What is the enthalpy of fusion for mercury (Hg), given that its normal freezing point is –38.9°C?
Which of the following reactions depicts standard enthalpy of formation values of zero?
Which of the following reactions depicts standard enthalpy of formation values of zero?
Flashcards
Entropy
Entropy
A measure of disorder or randomness in a system. Entropy increases when a system becomes more disordered.
Enthalpy (ΔH)
Enthalpy (ΔH)
The heat absorbed or released during a chemical reaction at constant pressure.
Gibbs Free Energy (ΔG)
Gibbs Free Energy (ΔG)
A thermodynamic potential that measures the spontaneity of a process. It combines enthalpy and entropy to determine if a reaction will occur spontaneously.
Calorimetry
Calorimetry
The study of heat transfer during chemical and physical changes.
Signup and view all the flashcards
Solubility
Solubility
The maximum amount of a substance that can dissolve in a given amount of solvent at a specific temperature.
Signup and view all the flashcards
Gibbs Free Energy Equation
Gibbs Free Energy Equation
ΔGrxn = ΔHrxn − TΔSrxn. Relates Gibbs Free Energy change to enthalpy, temperature, and entropy changes.
Signup and view all the flashcards
ΔE = q + w
ΔE = q + w
Change in internal energy equals heat plus work.
Signup and view all the flashcards
ΔS = q / T
ΔS = q / T
Change in entropy equals heat divided by temperature.
Signup and view all the flashcards
ΔG at Non-Standard Conditions
ΔG at Non-Standard Conditions
ΔG = ΔG° + RT(ln Q). Calculates Gibbs Free Energy change under non-standard conditions.
Signup and view all the flashcards
Equilibrium Constant
Equilibrium Constant
Keq = exp(−ΔG° / RT). This equation relates the equilibrium constant to the standard free energy change.
Signup and view all the flashcards
Specific Heat Capacity
Specific Heat Capacity
Cs = q / (m × ΔT). This equation relates specific heat capacity to heat, mass, and temperature change.
Signup and view all the flashcards
Heat Transfer in Calorimeter
Heat Transfer in Calorimeter
q = −Ccal × ΔT. Heat absorbed or released by a calorimeter equals the negative of the calorimeter's heat capacity times the temperature change.
Signup and view all the flashcards
Entropy Increase
Entropy Increase
Reactions with more moles of gas in the products than in the reactants tend to have increased entropy.
Signup and view all the flashcards
Standard Enthalpy of Formation
Standard Enthalpy of Formation
The standard enthalpy of formation of an element in its standard state is zero.
Signup and view all the flashcards
Work Done by Compression
Work Done by Compression
Work done in a compression process is calculated as w = -PΔV. Compression results in negative work.
Signup and view all the flashcards
State vs. Path Functions
State vs. Path Functions
State functions do not depend on the path taken (e.g., change in internal energy). Path functions, like work and heat, do depend on the path taken.
Signup and view all the flashcards
Enthalpy of Fusion
Enthalpy of Fusion
The heat required to melt a substance can be calculated using its enthalpy of fusion.
Signup and view all the flashcards
Heat of Reaction
Heat of Reaction
ΔHorxn = q / moles of phenol. Dividing the heat by the moles of phenol gives the change in enthalpy.
Signup and view all the flashcards
Solubility and Ksp
Solubility and Ksp
The lower the Ksp, the less soluble the salt.
Signup and view all the flashcardsStudy Notes
Exam 2 - Chemistry 1202
- Exam format: Closed notes, closed book, only a scientific calculator is allowed.
- Content: Includes questions that require understanding of entropy, enthalpy, Gibbs free energy, calorimetry, and solubility.
- Useful info:
- The periodic table is provided.
- Relevant equations:
- ΔGrxn = ΔHrxn − TΔSrxn
- ΔE = q + w
- ΔS = q / T
- ΔG = ΔG° + RT(ln Q)
- K eq = exp(−ΔG° / RT)
- Cs = q / (m × ΔT)
- q = −Ccal × ΔT
- Question 1:
- Understand which reaction leads to an increase in the entropy of the system.
- Entropy typically increases if products have more moles of gas than reactants.
- Question 2:
- Know that standard enthalpy of formation (∆Hof) is zero for elements in their standard state.
- Standard state: the most stable form of the element under standard conditions (298 K, 1 atm).
- Question 3:
- Calculate the enthalpy change (ΔH) for dissolving NaOH in water.
- Use the provided information: mass of NaOH, mass of water, initial and final temperatures, and specific heat of water.
- Remember that ΔH is negative for an exothermic reaction and positive for an endothermic reaction.
- Question 4:
- Calculate the work done in a compression process using the formula w = -PΔV.
- Note that work is negative for compression (volume decreases).
- Convert L-atm to J using 1 L-atm = 101.3 J.
- Question 5:
- Calculate the heat released in a reaction using the enthalpy of formation and the mass of the reactant.
- Use the stoichiometry of the balanced reaction to relate moles of reactant to moles of product.
- Question 6:
- Understand which processes depend on the path taken, meaning the work or heat involved changes depending on how the change occurs.
- Question 7:
- Calculate the heat required to raise the temperature of an aluminum cube using the formula q = mCΔT.
- Note that the specific heat of aluminum is given in J/g-C, so convert kg to g.
- Question 8:
- Understand the relationship between enthalpy of fusion and the heat required to melt a substance.
- Use the enthalpy of fusion and the molar mass of mercury to calculate the heat needed to melt a certain amount of mercury.
- Question 23:
- Calculate ΔGrxn at a specific temperature.
- Understand the relationship between ΔH, ΔS, and ΔG.
- The equation ΔGrxn = ΔHrxn − TΔSrxn is important for this calculation.
- Question 24:
- Calculate ΔG for a reaction at non-standard conditions and understand the relationship between ΔG°, partial pressures, and Kp.
- Utilize the equation ΔG = ΔG° + RT(ln Q), where Q is the reaction quotient.
- Question 25:
- Calculate the heat of reaction (ΔHorxn) for the combustion of phenol using calorimetry data.
- Remember ΔHorxn = q / moles of phenol.
- Ensure consistent units between the heat capacity of the calorimeter (kJ/°C) and the temperature change (°C).
- Question 26:
- Understand solubility and the relationship between Ksp and the concentration of ions in solution.
- The lower the Ksp, the less soluble the salt.
- The concentration of [Ag+] will be lowest in the salt with the smallest Ksp.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
