CH 15

± Using the Equilibrium Constant

1)

Part A

Initially, only A and B are present, each at 2.00 M. What is the final concentration of A once equilibrium is reached?

Part B

What is the final concentration of D at equilibrium if the initial concentrations are [A] = 1.00 M and [B] = 2.00 M ?

2)

Part A

A mixture initially contains A, B, and C in the following concentrations: [A] = 0.700 M , [B] = 1.20 M , and [C] = 0.600 M . The following reaction occurs and equilibrium is established:

A+2B⇌C

At equilibrium, [A] = 0.600 M and [C] = 0.700 M . Calculate the value of the equilibrium constant, Kc.

Express your answer numerically.

Part A

If Kb for NX3 is 4.0×10⁻⁶, what is the pOH of a 0.175 M aqueous solution of NX3?

Part B

If Kb for NX3 is 4.0×10⁻⁶, what is the percent ionization of a 0.325 M aqueous solution of NX3?

Express your answer numerically to three significant figures.

Part C

If Kb for NX3 is 4.0×10⁻⁶ , what is the the pKa for the following reaction?

HNX3+(aq)+H2O(l)⇌NX3(aq)+H3O+(aq)

Express your answer numerically to two decimal places.

Write the net ionic equation, including phases, for the dissolution of CaF₂(s) in H₃O⁺(aq).
Make sure your reaction is balanced, and do not include any spaces.

b. Briefly explain the differences between a boundary surface and the radial distribution function for hydrogenic atoms.

A solution contains 43.0 g of heptane (C7H16) and 46.0 g of octane (C8H18) at 25 ∘C. The vapor pressures of pure heptane and pure octane at 25 ∘C are 45.8 torr and 10.9 torr, respectively. Assuming ideal behavior, calculate each of the following.

The vapor pressure of heptane in the mixture.
The vapor pressure of octane in the mixture.
The total pressure above the solution.
What is the concentration of heptane in mass percent?
What is the concentration of octane in mass percent?

Why is the composition of the vapor different from the composition of the solution?

Hi, I had a quick question about hydrophobic and hydrophillic regions on a molecule.

I am confused on how to know if a molecule, which has both hydrophillic and hydrophobic regions, will be soluble in water or not? Can someone please explain in clear and simple words, thank you so much!

For example, in the molecule vitamin A, theres OH group which is hydrophillic but the rest of the molecule is hydrophobic, so how would I know if the whole molecule would be soluble in water or not?

Calculate the amount of energy in kilojoules needed to change 153 g of water ice at –10 ∘C to steam at 125 ∘C. The following constants may be useful: Cm (ice)=36.57 J mol−1 ∘C−1 Cm (water)=75.40 J mol−1 ∘C−1 Cm (steam)=36.04 J mol−1 ∘C−1 ΔfusH=+6.01 kJ mol−1 ΔvapH=+40.67 kJ mol−1

For the determination of the Fe in a Mohr's salt sample, do you expect to obtain more accurate results, with the data obtain after the direct titration using the indicator or with the data obtained with the potentiometric titration? Briefly justify your answer

What are the significance of bandstructure (E-k) plots? Which information we can get from E-k plots (obtained from DFT analyses) for materials? Please explain in details with some relevant diagrams or plots.

Please explain how to solve and show all work! I'm extremely lost.

Part 1:

A 180,000 gal. swimming pool requires treatment with 8.85 L of 7.00% "by mass" chlorinating solution to give chlorine level of 1.00 ppm (1.00 g chlorine per 10^3 kg of pool water). Based on these data, calculate d (in g/ml) for the chlorinating solution nothing that it is close to 1 g/mL. * "% by mass" means "mass of solute/100g solution". thus, this chlorinating solution contains 7.00 g chlorine/100 g chlorinating solution.

Part 2:

Take pool water as pure and, for the poo, calculate the H2O/Cl2 molecular ration after treatment with the 8.85 L of the chlorinating soln.

Part 3:

If density, d (pool water) = 1.00 g/mL, and d (chlorinating solution) = 1.10 g/mL, calculate volume, V, of chlorinating solution to add to the 180,000 gal pool water to up d of resulting pool wter to 1.01 g/mL.

25.0 mL of 0.200 M solution of HBr are mixed with 25.0 mL of 0.200 M solution of NaOH in a constant pressure calorimeter. The temperature increases from 23.00 °C to 24.37 °C. Assume that the specific heat of the solution is the same as that of pure water (4.18 J/(g•°C)) and that the density is the same as pure water (1.00 g/mL). Calculate ΔH per mole of reaction for the below chemical reaction.

HBr (aq) + NaOH (aq) → H₂O (l) + NaBr (aq)           

2.(3) Translate the following statement into a balanced chemical equation.

Three moles of calcium chloride react with two moles of sodium phosphate to produce solid calcium phosphate and six moles of sodium chloride.

3.(3) 50.0 mL of 1.0 M Ag(NO3) is added to 5.55 g of CaCl2 (MM=111.0 g). What is the concentration of nitrate ion in the final solution in moles/liter?

3a.(3) How many grams of silver chloride can be produced in this reaction?

at 25c the standard enthalpy of formation of HF(aq) is -320.1 kj/mol. of OH(aq) it is -229.6Kj/mol. of F (aq) it is -329.2 Kj/mol.of H2O(l) it is -285.9Kj/mol.

a. calculate the standard enthalpy of neutralization of HF.
HF (aq) + OH- (aq) -->F-(aq) +H2O (l)

b.using the value of -56.2kj as the standard enthalpy change for the reaction
H+(aq)+ OH(aq)->H2O(l)

c. calculate the standard enthalpy of change for the reaction
HF->H+F

Ro-vib spectroscopy observe what type of molecule? What is his energy range? Measured molecule properties.

If a small amount of the benzoic acid measured fails to dissolve in the lauric acid, what impact would this have on the molecular weight calculated? Would it be too high or too low? Explain your answer