1. The coordination number of a metal atom in a close-packed structure is?

2. The coordination number of a metal atom in a BCC structure is?

3. The coordination number of an atom in the diamond or zinc blende structure is?

4. Metallic hydrogen is a proposed high pressure state of hydrogen with exciting electrical properties. Calculations have been used to propose that this material will have a low coordination number. Of the three cubic structures we have discussed, body centered cubic is the most reasonable.

True or False?

Explain the relationship between light absorbance and solution concentration for a solution which obeys the Beer-Lambert law.

What is the pH of the solution made by mixing 0.2 mol NaH2PO4 and 0.5 mol NaOH with water to make 1.00 L of solution? The pKa values for H3PO4 are 2.12 7.20 and 12.

4) Formic acid (

What is the pH p H change of a 0.200 M M solution of citric acid (pKa=4.77 p K a = 4.77 ) if citrate is added to a concentration of 0.140 M M with no change in volume?

Calculate the enthalpy of oxidation per mole for N₂ and for C₂H₂ (the enthalpy of formation of N₂O₅(g) is 11.30 kJ/mol).

Two proteins with totally different primary structures are capable of binding calcium ions with very high affinity and selectivity. Give an explanation as to why two such proteins, with very different primary structures, would have this capability in common.

(a) Let us consider CH4 combustion in air with an equivalence ratio of 0.9, where we have air flow rate of 400 kg/s. (1) calculate the required flow rate of CH4 (in kg/s), the air-to-fuel ratio on mole basis, and the mole and mass fractions of CO2, H2O, O2, N2 in the product stream. (2) If reactants enter the combustion chamber at 790K, and the products are found to leave the chamber at 1900K, calculate the net heat loss from the combustion chamber. Use constant properties. For all product constituents, use properties near the average temperature of 1345K. (b) Through web search, write down the adiabatic flame temperatures for combustion in air with all reactants at STP, for methane, and hydrogen.

Design a protocol with a list of glassware needed and calculations to prepare a 100-mL homogeneous solution of HCl/FeCl3 with 0.025 M of FeCl3 and 0.10 M of HCL.

The following reagants are available:

3 M HCl and Solid FeCl3 . 6 H2O

Determine the percent yield for an acid/base reaction that involves mixing 500. mL of 0.100 molar nitric acid with 500. mL of 0.0500 molar barium hydroxide and a 0.00200 molar solution of barium nitrate is produced.

Using standard reduction potentials, calculate the standard emf, free energy, and equilibrium constant at 298K for each of the following reactions:

a. Cl2(g) + 2 I-(aq) → 2 Cl-(aq) + I2(s)

b. 2 NO3-(aq) + 8 H+(aq) 3 Cu(s) → 2 NO(g) + 4 H2O(l) + 3 Cu2+(aq)

c. Fe(s) + 2 Fe3+(aq) → 3 Fe2+(aq)

Ive posted this twice already and the answers have been really inconsistant

A 4.10 −g sample of a mixture of CaO and BaO is placed in a 1.00-L vessel containing CO2 gas at a pressure of 735 torr and a temperature of 26 ∘C. The CO2 reacts with the CaO and BaO, forming CaCO3 and BaCO3. When the reaction is complete, the pressure of the remaining CO2 is 155 torr .

Calculate the number of moles of CO2 that have reacted.

Calculate the mass percentage of CaO in the mixture.

Mobile charges of the following (if any):

Copper wire, Plastic, Sodium Carbonate, Aluminum Foil, Wood, Glass, Silver Wire, Graphite, Potassium Chloride, Lead, Silicon, Potassium accetate (solid), Potassium accetate (liquid), Dime, Sulfur, Sugar, Penny, Celery, HCI(g) in ligroin, 1.0M Sulfuric Acid, 1.0M ammonia solution, Acetic acid + ammonia miixture, .10M Sulfuric Acid, .10 Barium Hydroxide, Sulfuric acid + barium hydroxide, DI water, Tap Water, Pure Ethonal, Pure Acetic Acid, 95% Ethonal, .10M acetic Acid, .0010HCI, .010M HCI, .10M HCI, 1.0M HCI, Aqueous sodium carbonate, Aqueous calcium carbonate.

1.

Calculate the approximate pH of the following aqueous solutions at 25C. (Note: consider one decimal place for the pH answer.)

a) H₃PO₄ (0.20 M), (pK_a1=2.15, pK_a2=7.15, pK_a3=12.38)

b) Na₂CO₃ (0.20 M), (pK_a H₂CO₃/HCO₃^? = 6.35, pKa HCO₃^?/CO₃^2? = 10.30)

c) NaHCO₃ (0.20 M) (use pKa values from part "b" above)

a

b

c

2.

Calculate the approximate pH of the following aqueous solutions at 25C. (Note: consider one decimal place for the pH answer.)

a) NH₄Cl (0.20 M) + CH₃COONa (0.40M) , (pK_a NH₄⁺/NH₃ = 9.24, pK_aCH₃COOH/CH₃COO^? = 4.76)

b) NH₃ (0.040 M)+ NaOH (0.040M)

a

b

3.

Calculate the approximate pH of the following aqueous solutions at 25C. (Note: consider one decimal place for the pH answer.)

a) H₂S (0.10 M) + H₃PO₄ (0.20M) , (pK_aH₂S/HS^? = 7.02, pK_a HS^?/S^2? = 13.99, and H₃PO₄ pK_a values are given in part "a" of question 1)

b) H₃PO₄ (0.20M) + NaH₂PO₄ (0.10 M) (use pKa values given in question 1)

c) NH₄H₂PO₄ (0.1 0M) (pKa values are given in question 1 and 2 )

a

b

c

4.

A chemist prepares a solution that contains a formal concentration of 0.5 M phthalic acid and that has a pH of 2.88. What is the approximate fraction of phthalic acid in this solution at 25 C? Use 1 sig figs for the answer

Phthalic Acid: HOOCC₆H₄COOH/HOOCC₆H₄COO^- pKa1 = 2.95, HOOCC₆H₄COO^-/^-OOCC₆H₄COO^- pKa₂ = 5.41

Bonus: For more practice find the fractions of other species (forms) at this pH and decide which one is the predominant form. Plot an approximate curve of alpha vs pH for each species. You can hand them in for extra credit.

5.

How many grams of Ba(IO₃)₂ (FW=487 g/mol) can be dissolved in one liter of the following solutions at 25C? (Ba(IO₃)₂K_sp=1.57x10^?9) Use three significant figures for the answer. You do not need to consider the effect of electrolyte.

a) In water.

b) In a solution of Ba(NO₃)₂ (0.0700M)

a

b

6.

If a 0.100 M solution of NaOH is added to a solution containing 0.200 M Ni²⁺, 0.200 M Ce³⁺, and 0.200 M Cu²⁺, which metal hydroxides will precipitate first and last, respectively? K_sp for Ni(OH)₂ is 6.0x10^?16, for Ce (OH)₃ is 6.0 x 10^?22, and for Cu(OH)₂ is 4.8x10^?20.

A) Ni(OH)₂ first, Cu(OH)₂ last
B) Cu(OH)₂ first, Ni(OH)₂ last
C) Ni(OH)₂ first, Ce(OH)₃ last
D) Cu(OH)₂ first, Ce(OH)₃ last
E) Ce(OH)₃ first, Cu(OH)₂ last

Give detailed explanation