A ruby has a mass of 12.10 carats (1 carat = 200.0 mg). Rubies are made of crystalline from of Al2O3. What percentage of the mass of the ruby is aluminum? How many atoms of alluminum are in this ruby? The density of rubies is 4.02g/cm^3. What is the volume of the ruby?

Problem 20.26
A voltaic cell similar to that shown in Figure 20.5 in the textbook is constructed. One electrode compartment consists of an aluminum strip placed in a solution of Al(NO3)3, and the other has a nickel strip placed in a solution of NiSO4. The overall cell reaction is
2Al(s)+3Ni2+(aq)→2Al3+(aq)+3Ni(s)
Part A
What is being oxidized?
Express your answer as a chemical expression.

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Part B
What is being reduced?
Express your answer as a chemical expression.

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Part C
Write the half-reactions that occur in the two electrode compartments.
Express your answer as a chemical equation. Identify all of the phases in your answer.

anode reaction:
3Ni2++6e−→3Ni

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Part D
Express your answer as a chemical equation. Identify all of the phases in your answer.

cathode reaction:

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Part E
Which electrode is the anode, and which is the cathode?

Which electrode is the anode, and which is the cathode?

Al electrode is the anode, Ni electrode is the cathode.
Ni electrode is the anode, Al electrode is the cathode.

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Part F
Indicate the signs of the electrodes.

Indicate the signs of the electrodes.

Ni electrode is negative, Al electrode is positive.
Al electrode is negative, Ni electrode is positive.

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Part G
Do electrons flow from the aluminum electrode to the nickel electrode, or from the nickel to the aluminum?

Do electrons flow from the aluminum electrode to the nickel electrode, or from the nickel to the aluminum?

Electrons flow from the aluminum electrode to the nickel electrode.
Electrons flow from the nickel electrode to the aluminum electrode.

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Part H
In which directions do the cations and anions migrate through the solution? Assume the Al is not coated with its oxide.

In which directions do the cations and anions migrate through the solution? Assume the  is not coated with its oxide.

Cations migrate to the nickel electrode, anions migrate to the aluminum electrode.
Cations and anions migrate to the aluminum electrode.
Cations and anions migrate to the nickel electrode.
Cations migrate to the aluminum electrode, anions migrate to the nickel electrode.

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K_sp for PbCl₂ is 10^-5. Determine if a percipitate will form when following solutions are mixed:

100mL of 0.002 M Pb(NO₂₎₂ + 100mL 0.02 M KCl

Find molar solubility of BaF₂ (K_sp=10^-7) in 0.001 M NaF

Determine the rate law for the overall reaction (where the overall rate constant is represented as k).

Step 1 A -> B+C slow

step 2 C + D -> E fast

overall A+D -> B+E

Rate = ??

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3. Diet cola drinks have a pH of about 3.0, while milk has a pH of about 7.0. How many times greater is the H3O+ concentration in diet cola than in milk? A) 2.3 times higher in diet cola than in milk B) 400 times higher in diet cola than in milk C) 0.43 times higher in diet cola than in milk D) 1,000 times higher in diet cola than in milk E) 10,000 times higher in diet cola than in milk

4. A 5.5 L sample of a 0.25 M HNO3 solution is mixed with 1.2 L of a 0.34 M HCl solution. What is the pH of the mixture? A) 0.23 B) 0.57 C) 1.07 D) 0.50 E) 0.84

5. Predict the direction in which the equilibrium will lie for the reaction H3PO4(aq) + HSO4–(aq) H2PO4–(aq) + H2SO4(aq). Ka1(H3PO4) = 7.5 × 10–3; Ka(H2SO4) = very large A) to the right B) to the left C) in the middle

6. Predict the direction in which the equilibrium will lie for the reaction H2SO3(aq) + HCO3– (aq) HSO3–(aq) + H2CO3(aq). Ka1(H2SO3) = 1 × 10–2; Ka1(H2CO3) = 4.2 × 10–7 A) to the right B) to the left C) in the middle

7. Which one of these salts will form a basic solution upon dissolving in water? A) NaI B) NaF C) NH4NO3 D) LiBr E) Cr(NO3)3

8. Which one of these salts will form an acidic solution upon dissolving in water? A) LiBr B) NaF C) NH4Br D) KOH E) NaCN

9. Which one of the following salts will form an acidic solution on dissolving in water? A) LiBr B) NaF C) KOH D) FeCl3 E) NaCN

Explain the significance of charge balance and mass balance.

III. Buffer Solutions

A. Buffer 1

i. Measure out 10.0 mL of 1.0 M CH₃COOH and 25.0 mL of 1.0 M sodium acetate (NaCH₃COO) into a beaker

2. What is the concentration of acetic acid in this solution after mixing. (include units) [CH₃COOH] ?

3. What is the concentration of acetate ion in this solution after mixing.(include units) [CH₃COO^-] ?

4. Calculate the expected pH of this buffer solution.

5. Measured pH of this buffer solution pH: 5.31

I have no idea how to do number 2,3,4 and I have to repeat these processes/ questions for different solutions. If you could show me how to do these, I would greatly appreciate it! Thank you so much in advance.

1.  The dipole moment of BrCl is 0.518 D and the distance between atoms is 213.9 pm. What is the percent ionic character of the BrCl bond?

A first-order reaction has a half-life of 17.3 minutes. What is the time required for the reactant concentration to decrease to 2.0% of it's origional value?

Thank you!

An aqueous solution contains 0.392 M ethylamine (C₂H₅NH₂).

How many mL of 0.313 M hydrobromic acid would have to be added to 225 mL of this solution in order to prepare a buffer with a pH of 10.700?

Why would a repeating unit of PET (polyethyleneterephthalate) be used to calculate the limiting reagent and yield instead of the molecular weight of the polymer? Is it just because it is a polymer and only its monomer needs to be taken into account?

Caffeine, a stimulant found in coffee, tea, and energy drinks, contains C, H, O, and N.
Combustion of 1.000 mg of caffeine produces 1.813 mg CO2, 0.4639 mg H2O, and 0.2885 mg N2.
Calculate the molecular formula of caffeine, whose molar mass lies between 150 and 200 g/mol.

In step four of glycolysis, the C6 species is split into two C3 species, the two trioses that are produced are not identicle. Name these two trioses. Which of these two C3 species is a glycolysis intermediate? What is the fate of the other triose?

In discussing molecular rotation, the quantum number JJ is used rather than ll. The bond length is 141.4pmpm.

Part A : Calculate E_rot/K_BT for ¹H^{_^81}Br  for J=0 at 334 KK .

Part B: Calculate E_rot/K_BT  for ¹H⁸¹Br for J =5 at 334 KK .