Which solids are used to make a solid oxide fuel cell?
2. What is/are the fuels operating SOFCs?
3. What do we know about the atomic structures, i.e. lattices and unit cells of SOFCs?
<sub>4.Where are the materials (chemicals) resources from? Are they abundant?
5. What are potential environmental issues associated with the resourcing and production of those SOFC components?</sub>

A beaker with 105 mL of an acetic acid buffer with a pH of 5.000 is sitting on a benchtop. The total molarity of acid and conjugate base in this buffer is 0.100 MM. A student adds 9.00 mL of a 0.460 M HCl solution to the beaker. How much will the pH change? The pKa of acetic acid is 4.740.

Express your answer numerically to two decimal places. Use a minus ( − ) sign if the pH has decreased.

Describe how to separate a mixture containing phenol, aniline, benzoic acid, and toluene.

1. What is the pH at the equivalence point in the titration of a 18.7 mL sample of a 0.381 M aqueous hydrocyanic acid solution with a 0.496 M aqueous sodium hydroxide solution?

pH =

2. The solubility of Ag₂S is measured and found to be 7.38×10^-15 g/L. Use this information to calculate a K_sp value for silver sulfide.

Ksp =

1) determine the heat of reaction from the bond enthalpies for the reaction given

H2      +     Br2   >>    2 HBr

436.4         192.5            366.1

2) calculate the formal charges in the phosphate ion.

3) what elements can have "expanded octets" and how many electrons can they carry?

Imagine an alternate universe where the value of the Planck constant is 6.62607·10^8 J·s

.In that universe, which of the following objects would require quantum mechanics to describe, that is, would show both particle and wave properties? Which objects would act like everyday objects, and be adequately described by classical mechanics?

1. A buckyball with a mass of 1.2 x 10^-21 g, 0.7 nm wide, moving at 16. m/s.

Classical or Quantum

2. An airplane with a mass of 1.58 x 10⁴ kg, 13.0 m long, moving at 800. km/h.

Classical or Quantum

3. A turtle with a mass of 720. g, 28. cm long, moving at 1.7 cm/s.

Classical or Quantum

4. An eyelash mite with a mass of 11.8 µg, 340 µm wide, moving at 50. µm/s.

Classical or Quantum

What are the empirical formulas of substances with the following mass percent compositions?

(a) aspirin 4.48% H, 60.00% C, 35.52% O

(b) ilmenite (a titanium-containing ore) 31.63% O, 31.56% Ti, 36.81% Fe

(c) sodium thiosulfate (photographic "fixer") 30.36% O, 29.08% Na, 40.56% S

When Iodobenzene  (b.p. 188.5 oC) codistills with water at 760 torr, the boiling point of the mixture is 98.5 oC.  The vapor pressure of water at 98.5 oC is 714 torr.

What is the partial pressure of iodobenzen at 98.5oC?

Calculate the weight of the iodobezene that codistills with each gram of water at 98.5 0C.

Calculate the weight of water needed to codistill 1.5 g idobenzene using steam distillation. 

Does the molecule of Succinic acid rotate around its central c-c bond?

Calculate the mass of methane that must be burned to provide enough heat to convert 347.0 g of water at 18.0°C into steam at 110.0°C.

(Assume that the H₂O produced in the combustion reaction is steam rather than liquid water.)

I don't know to do ii) for letter a, as well as letter d, e and the EC . Can you help?

The combustion of carbon monoxide is represented by the equation below:

CO(g) + ½O 2 (g) → CO 2 (g)

(a) (i) Determine the value of the standard enthalpy change, ΔH o rxn, for the combustion of CO(g) at
298 K using the following information. (3 pts)

C(s) + ½O 2 (g) → CO(g) ΔH o 298 = -110. 5 kJ mol -1
C(s) + O 2 (g) → CO 2 (g) ΔH o 298 = -393.5 kJ mol -1

(ii) Which is larger, the total bond dissociation energy of the reactants or the total bond
dissociation energy of the products? Explain. (2 pts)

(b) Determine the value of the standard entropy change, ΔS o rxn , for the combustion of CO(g) at 298
K using the information in the following table. (3 pts)
Substance S o 298(J mol -1 K -1 )
CO(g) 197.7
CO 2 (g) 213.7
O 2 (g) 205.1

(c) i) Determine the standard free energy change, ΔG o rxn , for the reaction at 298 K. Include units with
your answer. (3 pts)

ii) Is the reaction spontaneous under standard conditions at 298 K? Justify your answer. (2 pts)

(d) Calculate the value of the equilibrium constant, K eq , for the reaction at 298 K. (3 pts)

(e) Assume ∆H o and ∆S o for the reaction are independent of temperature.
(i) Explain why there is a temperature above 298 K at which the algebraic sign of the value of
∆G o changes. (2 pts)

(ii) Theoretically, the best yield of CO 2 should be achieved at low temperatures or high
pressures. Explain each. (hint: apply Le Chatelier’s principle) (2 pts)

EC a) Write a net ionic equation for: Lithium metal is strongly heated in nitrogen gas. (2 pts)

b) Predict the sign of ΔS° for the reaction at 25°C. Justify your prediction. (1 pt)

In the laboratory you dissolve 13.2 g of iron(III) acetate in a volumetric flask and add water to a total volume of 500 mL.

What is the molarity of the solution?  M.

What is the concentration of the iron(III) cation?  M.

What is the concentration of the acetate anion?  M.