3. The

Part A What is the pH of a buffer prepared by adding 0.809 mol of the weak acid HA to 0.608 mol of NaA in 2.00 L of solution? The dissociation constant Ka of HA is 5.66×10−7. Part B What is the pH after 0.150 mol of HCl is added to the buffer from Part A? Assume no volume change on the addition of the acid. (Express answer to 3 decimal places) Part C What is the pH after 0.195 mol of NaOH is added to the buffer from Part A? Assume no volume change on the addition of the base.

A voltaic cell is constructed that uses the following reaction and operates at 298 K:
Zn(s)+Ni2+(aq)→Zn2+(aq)+Ni(s).

a. What is the emf of this cell when [Ni2+]= 2.10 M and [Zn2+]= 0.160 M ?

b. What is the emf of the cell when [Ni2+]= 0.100 M and [Zn2+]= 0.860 M ?

Thanks!

The atmosphere slowly oxidizes hydrocarbons in a number of steps that eventually convert the hydrocarbon into carbon dioxide and water. The overall reactions of a number of such steps for methane gas is as follows:
CH4(g)+5O2(g)+5NO(g)→CO2(g)+H2O(g)+5NO2(g)+2OH(g)
Suppose that an atmospheric chemist combines 145 mL of methane at STP, 895 mL of oxygen at STP, and 54.5 mL of NO at STP in a 2.0 −Lflask. The reaction is allowed to stand for several weeks at 275 K.

Part A

If the reaction reaches 90.0% of completion (90.0% of the limiting reactant is consumed), what are the partial pressures of each of the reactants in the flask at 275 K?

Enter your answers numerically separated by commas.

Part B

If the reaction reaches 90.0% of completion (90.0% of the limiting reactant is consumed), what are the partial pressures of each of the products in the flask at 275 K?

Enter your answers numerically separated by commas.

Part C

What is the total pressure in the flask?

Calculate the freezing point and boiling point in each solution, assuming complete dissociation of the solute.

a)Calculate the freezing point of a solution containing 10.8

g FeCl3 in 172 g water.

b)Calculate the boiling point of a solution above.

c)Calculate the freezing point of a solution containing 4.3 % KCl

by mass (in water).

d)Calculate the boiling point of a solution above.

e)Calculate the freezing point of a solution containing 0.155 m MgF2.

f)Calculate the boiling point of a solution above.

Which of the following are true statements about equilibrium systems?

True/False For the following reaction at equilibrium:
                       2 H₂(g) + O₂(g) ⇌ 2 H₂O(g)
                       the equilibrium will shift to the left if the volume is doubled.

True/False For the following reaction at equilibrium:
                       H₂(g) + F₂(g) ⇌ 2HF(g)
                       removing H₂ will decrease the amount of F₂ present once equilibrium is reestablished.

True/False For the following reaction at equilibrium:
                       CaCO₃(s) ⇌ CaO(s) + CO₂(g)
                       adding more CaCO₃ will shift the equilibrium to the right.

True/False Increasing the temperature of an exothermic reaction shifts the equilibrium position to the right.

True/False For the following reaction at equilibrium:
                       CaCO₃(s)⇌ CaO(s) + CO₂(g)
                       increasing the total pressure by adding Ar(g) will shift the equilibrium to the right.

A piece of copper wire is 50ft long and has a dimater of 2.0 mm. Copper has a denisty of 8.92 g/cm³. What is the mass of copper? Express the answer in kg. (1ft = 30.48 cm, 1 cm = 10 mm and Volume is 3.14 x r²x1)

Please explain and help ! :(

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)

1. What is being reduced?

2. Write the half-reactions that occur in the two electrode compartments.

anode reaction:

cathode reaction:

How many grams of Na2CO3 should be mixed with 5.00 g of NaHCO3 to produce 100 mL of buffer with a pH of 10.00? What volume of 0.01 M NaOH must be added to this solution to achieve a pH of 11.25? (pKa1 is 6.35; pKa2 is 10.53)

Using energy level diagrams, predict the relative stability of a Br₂ molecule as well as the first excited state.

1a) A sample of a new cleaning product, "Joe's Famous Bleach Cleaner," with a mass of 59.0 g , was diluted with an acetic acid solution containing excess I−. A small amount of starch indicator solution was then added, turning the solution a deep bluish-purple. The solution was then titrated with 0.190 M sodium thiosulfate, Na2S2O3, containing the ion S2O32−. A volume of 45.0 mL of sodium thiosulfate, the titrant, was needed to turn the solution colorless. What is the percentage composition by mass of NaClO in the bleach product?

1b) A stainless steel alloy is to be analyzed for its chromium content. A 3.50 g sample of the steel is used to produce 250.0 mL of a solution containing Cr2O72−. A 10.0-mL portion of this solution is added to BaCl2(aq). When the pH of the solution is properly adjusted, 0.145 g BaCrO4(s) precipitates. What is the percent Cr, by mass, in the steel sample?

What is the VSEPR sketch of PO2-

Explain the relation between muscles, ATP energy, and the calcium ion

What is the % concentration (m/v) of a solution prepared by dissolving 10.0g of NaOH in enough water to make 225mL of solution?

What is the resonance structure for SeO₂ and how is the bond lenght compared to an isolated single or double bond?