General Chemistry
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Classify the following processes as spontaneous or nonspontaneous:
A. An icicle melting on your hand on a cold day
B. Conversion of water into steam at 120 °C
C. A stone rolling uphill
D. Dissolution of salt in water
Which of the following statements are correct?
i. The reverse direction of a spontaneous reaction will be nonspontaneous under the same reaction conditions.
ii. Spontaneous processes are slow.
iii. All reversible reactions are spontaneous.
iv. There is no heat loss in an isothermal process.
v. A reversible process can produce more work than an irreversible process
The refrigerant used in air-conditioning systems can easily undergo vaporization at atmospheric pressure and compression at higher pressures. The system then acts as a closed system consisting of the refrigerant undergoing these two stages. The vaporization occurs in an expansion chamber at low pressures. The compression of the vapor back to its liquid phase occurs in a compression chamber at high pressure.
A house and its exterior are initially 35 °C. After turning on the air conditioner, the house is cooled to 25 °C. Is this process nonspontaneous or spontaneous?
True or False. The reaction of N2(g) and CO2(g) occurs spontaneously to produce NO(g) and CO(g) at room temperature and 1 atm
Is the ripening of a mango a spontaneous or nonspontaneous process?
Identify which of the processes below are non-spontaneous and state if the non-spontaneous processes are impossible.
i. water falling from waterfalls
ii. riding a skateboard uphill
iii. boiling of water
iv. turning graphite into diamond
Identify which of the processes below are non-spontaneous.i. formation of rust in iron exposed to airii. photosynthesisiii. dissolution of salt in wateriv. melting of ice on a hot summer day
For a non-spontaneous process, which of the following statements is true?
I. The process will occur given enough time.
II. The process will never occur.
III. The process will occur in the presence of an external influence.
Use the data below to create an approximate graph of the standard molar entropy against temperature for methanol from 0 K to 400 K:
melting point = –98°C
boiling point = 65°C
S°(l) = 126.8 J/(mol•K) at 25 °C.
The ∆Hfus and ∆Sfus for glucose are 19.93 kJ/mol and 47.5 J/(K·mol), respectively. At 100 °C, does glucose melt? If not, what is the melting point for glucose?
The ∆Hvap and ∆Svap for acetone are 31.3 kJ/mol and 95 J/(K·mol), respectively. At 40 °C and 1 atm of pressure, does acetone boil? If not, what is its normal boiling point?
The ΔHvap for octanol is 70.1 kJ/mol. It has a boiling point of 195 °C. What is its ΔSvap?
Given that mp = –26 ºC and ΔHfus = 9.32 kJ/mol for benzaldehyde, calculate ΔSfus (in J/mol K).
Identify the ΔSsurr of the reaction given the following: ΔH°rxn = +156 kJ and T = 112 K
Consider a system with 3.62 mole of Acetone (C3H6O). Calculate the change in entropy that occurs in the system when it condenses at its boiling point of 56.1 °C and the heat of vaporization is 29.1 kJ/mol
Consider a system with 1.26 mole of Acetone (C3H6O). Calculate the change in entropy that occurs in the system when it melts if its melting point is -94.8 °C and the heat of fusion of is 5.69 kJ/mol
Given the following data:
Calculate ΔSfus and ΔSvap for K.
ΔSfus = _________ J•K–1•mol–1
ΔSvap = _________ J•K–1•mol–1
According to Trouton's rule, all liquids have a roughly constant ratio between their molar heat of vaporization and normal boiling point (measured in kelvin): ΔHvap/Tbp = 88 J/(K·mol). Consider the following liquids in the table:
Identify which liquid deviate(s) from Trouton's rule. Explain.
According to Trouton's rule, all liquids have a roughly constant ratio between their molar heat of vaporization and normal boiling point (measured in kelvin): ΔHvap/Tbp = 88 J/(K·mol)
Why do liquids have the same ΔHvap/Tbp value?
According to Trouton's rule, all liquids have a roughly constant ratio between their molar heat of vaporization and normal boiling point (measured in kelvin): ΔHvap/Tbp = 88 J/(K·mol). Verify Trouton's rule's reliability for the liquids indicated in the following table.
Trouton's rule state that the standard molar entropy of vaporization for many liquids at their normal boiling points is about 88 J/mol-K. What is the normal boiling point of I2 (ΔH°vap I2(g) = 62.4 kJ/mol, ΔH°vap I2(l) = 13.5 kJ/mol) assuming that Trouton's rule applies and its ΔH°vap remains constant with temperature?
Identify which of the following compounds follow Trouton's rule.
For a given process, the number of microstates increased. How is this related to ΔSsys?
There are two boxes containing five balls each. The balls are labeled from 1 to 5. One ball is drawn from each box. How many ways can the drawn balls get a sum of 4? Determine the most probable total.
Four boxes (1, 2, 3, and 4) of equal volume are distributed with ideal gas molecules. In how many ways can the following states be attained? Determine the entropy for each state using Boltzmann's equation.
(i) 3 molecules in box 1
(ii) 3 molecules randomly distributed among boxes 1, 2, 3, and 4
Specify whether each claim is true or false.
(a) At a given temperature, SO3(g) and Kr(g) will have the same number of microstates because they have almost the same molar mass.
(b) Heating a gas like SO2(g) will not affect the degrees of translational, rotational, and vibrational motions.
(c) The absolute values of enthalpy and entropy can be both determined.
If the state of the system consisting of three standard playing dice is determined by the sum of the values displayed on the top faces of the three dice, what is the system's absolute entropy?
What happens to the number of microstates when the volume of the system decreases?
The entropy of a system decreases as it goes to state B from state A. Will its number of microstates increase or decrease?
Differentiate a microstate of a system from a state of a system
A law of thermodynamics states that "The entropy of a perfect crystalline solid is zero when the temperature is equal to absolute zero (0 K)." This is law is the
There are two possible ways to roll a 3 using two dice each numbered 1-6. Therefore, there are two microstates for the outcome of 3 (a specific microstate). Determine the number of possible ways to roll a 4. Calculate the entropy associated with an outcome of 4. (KB = 1.38×10–23)
The internal energy of a substance can reach zero when the substance is cooled all the way to absolute temperature (T = 0 K). Is this statement true or false?