a)Calculate the equilibrium constant at 10 K for a reaction with ΔHo = 10 kJ and ΔSo = 100 J/K.
b) Calculate the equilibrium constant at 105 K for the thermodynamic data in the previous question.
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1000 m3 of moist air at 101 kPa and 25 °C with a dew point of 11 °C enters a process. The air leaves the process at 98 kPa with a dew point of 58 °C. Assume ideal gases.
(a) Draw and label a flowsheet for the process.
b) What is the mole fraction of water in the air entering the process? Leaving the process?
(c) How many moles of water are added to or removed from the 1000 m3 of moist air?
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I have had such a hard time figuring out this problem please show with detailed response! thank you
Consider the titration of a 23.0?mL sample of 0.175M CH3NH2 with 0.155M HBr. Determine each of the following.
1.the initial pH
2.the volume of added acid required to reach the equivalence point
3.the pH at 6.0mL of added acid
4.the pH at one-half of the equivalence point
5.the pH at the equivalence point
6.the pH after adding 6.0mL of acid beyond the equivalence point
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A. Write the Ksp expression for the sparingly soluble compound silver phosphate, Ag3PO4. Ksp=?
B. Write the Ksp expression for the sparingly soluble compound barium phosphate, Ba3(PO4)2. Ksp=?
C. The solubility of PbF2 is measured and found to be 0.527 g/L. Use this information to calculate a Ksp value for lead fluoride. Ksp=?
D.The solubility of Ag2CO3 is measured and found to be 3.55E-2 g/L. Use this information to calculate a Ksp value for silver carbonate. ksp=?
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Write the balanced chemical equation for ethanol C2H6O burning in air as a LEAN mixture if the reactant side of the reaction is C2H6O + ?(O2 + 3.76N2) ===> ? CO2 + H2O + ? ?????
NOTE: A LEAN mixture means you have more air than you need to burn all the fuel. You will have excess oxygen left over after the reaction process.
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Volumes and molarities for titration of CdC2O4 solutions.
PART A Data
Initial reading of buret (KMnO4) (mL) 0.50
Final Reading of buret (KMnO4) (mL) 14.00
Molarity of KMnO4 solution (M) 0.000969
PART B DATA
Initial Reading of buret (NH3) (mL) 1.00
Final reading reading of buret (NH3) mL 22.50
Molarity of NH3 solution (M) 5.00
FOR PART A Find:
Moles of MnO4- used for titration (mol)
Moles of C2O42- in 100.0mL of solution (mol)
Molarity of C2O42-(M)
Molarity of Cd2+ (M)
Ksp of CdC2O4
For PART B Find:
Total Moles of C2O42-
Molarity of C2O42- (M)
Total moles of Cd2+ (mol)
Moles of [Cd(NH3)4 2+] (mol)
Molarity of [Cd(NH3)4 2+] (M)
Moles of NH3 added by titration (mol)
Moles of NH3 that did not react with Cd2+ (mol)
Molarity of NH3 that did not react with Cd2+ (M)
Kf for [Cd(NH3)4 2+]
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Gold is isolated from rocks by reaction with aqueous cyanide, CN-: 4 Au(s) + 8NaCN(aq)+O2(g)+H20(l)-> 4Na[Au(CN)2](aq)+4NaOH(aq). (a)Which atoms from which compounds are being oxidized, and which atoms from which compounds are being reduced? (b) The[Au(CN)2]- ion can be converted back to Au(0) by reaction with Zn(s) powder. Write a balanced chemical equation for this reaction. (c) How many liters of a 0.200 M sodium cyanide solution would be needed to react with 40.0kg of rocks that contain 2.00% by mass of gold?
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Draw a log modulus–temperature plot for an amorphous polymer. What are the five regions of viscoelasticity, and where do they fit? To which regions do the following belong at room temperature: chewing gum, rubber bands, Plexiglas®?
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1. A state has an energy = 76.5×10−21 J and a degeneracy of 15. What is the free energyof the state at 25◦C and at 150◦C? Express your answer in kJ/mol.
2. A molecule has a bond that can rotate between the cis and trans
states, both of whichhave zero entropy. It is found that the trans
state is three times more common than thecis state when the
temperature is 250 K. If the molecule is heated to 450 K, what is
thenew ratio of trans to cis?
3. A system consists of two independent subsystems, A and B.
Subsystem A has 1.3 × 106
allowed microstates and subsystem B has 4.6 × 107 allowed
microstates. What is theentropy of the combined system?
4. Macrostate X consists of 5 microstates, each of which have an
energy of x = 1.5×10−21
Joules. Macrostate Y consists of 150 microstates, each of which
have an energy y =7.0 × 10−21 J. Calculate probability that the
system is in state X if the temperature is25◦C.
5. A molecular system at room temperature (25◦C) is found with
energy EA 95% of thetime and with energy EB 5% of the time. It is
known that state A consists of an ensembleof 3 microstates while
there are only 2 microstates in state B. Determine the differencein
energies between the two states (EA − EB).
6. Chemical reactions are often described using a three state
modelReactants → Transition State → ProductsIn most cases the
energy of the transition state is much higher than the energy of
the
reactant state. This means that the reaction cannot proceed until
there is a randomthermal fluctuation large enough to ‘kick’ the
reactant molecule(s) up to the transitionstate energy. Say we have
a reaction in which the transition state is 9.0 × 10−20 J abovethe
reactant state.
(a) Calculate the ratio of the probability the system is in the
transition state to the probability
that it is in the reactant state PTS/PR at 37◦C.
(b) Use your answer above to estimate the time it takes for the reaction to occurspontaneously at 37◦C. Assume that the system samples a new microstate everynanosecond (10−9 s).
(c) One way to speed up the reaction is to heat the system. If the
temperature isincreased to 1000 K, how long does it take for the
reaction to occur?
(d) In biological systems it is not feasible to accelerate
reactions by heating them to1000 K. Instead, the reactions rely on
enzymes that catalyze reactions by loweringthe energy of the
transition state. If catalyzed reaction has a transition state
energy2.0 × 10−20 J, what is the approximate reaction time? Use a
temperature 37◦C.
1
(e) Finally, estimate the uncatalyzed reaction time if the transition state is not a uniquemicrostate, but actually an ensemble of 100 microstates. Use a temperature 37◦C.
7. A salt ion is dissolved in a large volume of pure water. The
wall of the container has asingle defect that can bind the ion with
an energy bound = −2.1 × 10−19 J.
(a) If the ion is only bound to the impurity site 2% of the time at
room temperature(25◦C), what is the free energy of the ion in the
unbound state? Assume that thefree energy of the bound state is
equal to the binding energy (the state is non-degenerate).
(b) Calorimetry experiments reveal that the energy of the ion in the unbound state issolv = −5.1 × 10−20 J. Is the change in energy bigger or smaller than kBT at roomtemperature? [i.e. calculate (solv − bound)/kBT]
(c) What is the entropy of the unbound state?
(d) How many microstates are in the unbound ensemble?
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The solubility of barium carbonate, BaCO3, is 0.0100 g/L. Its molar mass is 197.3 g/mol. What is the Ksp of barium carbonate?
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Calculate the pH of a 0.51 M CH3COONa solution. (Ka for acetic acid = 1.8x10^-5)
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Assume you are carrying out the titration of 50 mL of a 0.025 M solution of acetic acid with 0.1023 MNaOH. Acetic acid has aKaof 1.8×10−5.
(a) Calculate the pH of the solution at V= 0, V= 0.3Veq, V=Veq, and V= 1.2Veq. (Veq is the equivalence point volume)
(b) If a phenolphthalein indicator was used in this titration, where would the apparent endpoint occur? Assume the apparent endpoint would occur at the end of the color range of the indicator (pH’s of 8.0-9.6).
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1)
A 1.0-L buffer solution is 0.125 M in HNO2 and 0.180 M in NaNO2.
Part A
Determine the concentrations of HNO2 and NaNO2 after addition of 1.5 g HCl.
Express your answers using three significant figures separated by a comma.
Part B
Determine the concentrations of HNO2 and NaNO2 after addition of 1.5 g NaOH.
Express your answers using three significant figures separated by a comma.
Part C
Determine the concentrations of HNO2 and NaNO2 after addition of 1.5 g HI.
Express your answers using three significant figures separated by a comma.
2)
A 1.0 L buffer solution is 0.250 M HC2H3O2 and 0.050 M LiC2H3O2. Which of the following actions will destroy the buffer?
A 1.0 L buffer solution is 0.250 M HC2H3O2 and 0.050 M LiC2H3O2. Which of the following actions will destroy the buffer?
adding 0.050 moles of LiC2H3O2 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
adding 0.050 moles of NaOH | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
adding 0.050 moles of HC2H3O2 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
adding 0.050 moles of HCl | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
None of the above will destroy the buffer. 3) Part A Write a balanced equation for the dissolution of CaCO3. Express your answer as a chemical equation. Identify all of the phases in your answer. Part B Write an expression for Ksp for the dissolution of CaCO3. Write an expression for for the dissolution of .
|
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What is the potential of a galvanic cell made up of Cd/Cd2+ and Ag/Ag+ half-cells at 25
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