Write balanced molecular and net ionic equations for the reaction that occurs when

     each of the following is added to a perchloric acid solution.

     a) a barium hydroxide solution

      b) solid barium sulfate

c) aluminum metal

A 54.1 mg sample of sodium perchlorate contains radioactive chlorine-36 (whose atomic mass is 36.0 amu).

1. If 29.6% of the chlorine atoms in the sample are chlorine-36 and the remainder is naturally occurring nonradioactive chlorine atoms, how many disintegrations per second are produced by this sample?

The half-life of chlorine-36 is 3.0×105 yr.

At a fixed temperature, equal moles of N₂ (g) and F₂ (g) are mixed in a constant pressure container (the volume of the container changes in order to keep the pressure at a constant value). The N₂ (g) and F₂ (g) are allowed to react, producing NF₃ (g):

N₂ (g) + 3F₂ (g) ? 2 NF₃ (g)

If the initial volume of the container, before any reaction takes place, is 4.10 L, determine the volume of the container after the N₂ (g) and F₂ (g) have reacted to completion.

The final volume will be  L

Laboratory question:

I have a solution of a known amount of Sulfuric acid as a catalyst. The reaction is a esterfication of the two reactants ethanol and acetic acid with known amounts, and the Product is ethyl acetate and water. When the reaction reach equilibrium, the purpose is to figure out how much acetic acid is left (still reactant). The only permissible method for this is titration with NaOH and find the amount unreacted acetic acid, but there is a problem, we also have the catalyst in the solution. How can we make a titration and figure out the amount of acetic acid ?

Consider an electrochemical cell involving the overall reaction

2 AgBr(s) + Pb(s) → Pb2+(aq) + 2 Ag(s) + 2 Br–(aq)

Each half-reaction is carried out in a separate compartment. The anion included in the lead half-cell is NO3–. The cation in the silver half-cell is K+. The two half-cells are connected by a KNO3 salt bridge. If [Pb2+] = 1.0 M and [Br-] = 0.14 M, what is the emf of the cell at 298 K?
Given:

AgBr(s) + e– → Ag(s) + Br–(aq)              E° = +0.07 V.

Pb⁺² + 2e– → Pb(s)                                E° = - 0.13 V.

A 16.0 mL sample of a 1.56 M potassium sulfate solution is mixed with 14.3 mL of a 0.890 M barium nitrate solution and this precipitation reaction occurs: K2SO4(aq)+Ba(NO3)2(aq)→BaSO4(s)+2KNO3(aq) The solid BaSO4 is collected, dried, and found to have a mass of 2.51 g . Determine the limiting reactant, the theoretical yield, and the percent yield

If a 0.200 M solution of KOH is added to a solution containing 0.100 M Ni2+, 0.100 M Ce3+, and 0.100 M Cu2+, which metal hydroxide will precipitate first? Calculate the concentration of the first precipitated ion when the second soluble ion begins to precipitate. When the most soluble ion starts to precipitate, what is the concentration for the second soluble ion in the solution?

Ksp Ni(OH)2 = 6.0 X 10-16, Ksp Ce(OH)3 = 6.0 X 10-22, Ksp Cu(OH)2 = 4.8 X 10-20

Heptane and water do not mix, and heptane has a lower density (0.684 g/mL) than water (1.00 g/mL). A 100 mL graduated cylinder with an inside diameter of 3.200 cm contains 39.0 g of heptane and 32.0 g of water. Before we can determine the height of the liquid column, we need to know the total volume of liquid in the cylinder. Which equation expresses the total volume in terms of the volumes of heptane and water?

5) Which of the following statements correctly describe(s) E1 reactions of alkyl halides (RX)?

I.    Rate = k[base]

II. Rate = k[base][RX]

III.       Rate = k[RX]

IV.       The reactions occur in two distinct steps.

V. The reaction involves a carbocation intermediate.

Given the values of ΔH∘rxn , ΔS∘rxn , and T below, determine ΔSuniv .

ΔH∘rxn= 90 kJ , ΔSrxn= 145 J/K , T= 308 K

ΔH∘rxn= 90 kJ , ΔSrxn= 145 J/K , T= 757 K

ΔH∘rxn= 90 kJ , ΔSrxn=− 145 J/K , T= 308 K

ΔH∘rxn=− 90 kJ , ΔSrxn= 145 J/K , T= 403 K

Please show work.

Spontaneous or not?

Approximate the percent increase in waist size that occurs when a 135 lb person gains 35.0 lbs of fat. Assume that the volume of the person can be modeled by a cylinder that is 4.0 feet tall. The average density of a human is about 1.0 g/cm^3 and the density of fat is 0.918 g/cm^3

Express your answer using two significant figures.

50mL of solution in which the analytical concentration of benzoic acid is 0.124 M is titrated with 0.261 M NaOH; if V_e is the volume needed to reach the endpoint, what is the pH at 0 Ve, 1/4 Ve, 1/2 Ve, Ve, and 1.212 Ve?

There are 220 million motored vehicles in the USA, of which about 85% operating on gasoline-fired Otto engines. Gasoline can be assumed 100% octane (C8H18) with a heating value of 48,000 kJ/kg, specific gravity of 0.83, and price of $2.50/gallon. A typical vehicle uses 15% excess air in combustion, and is driven an average of 32 miles per day per vehicle, with an average fuel economy of 18 miles per gallon of gasoline. The averaged unburned Hydrocarbons, CO, and NOx, emissions amount to 0.3%, 0.05%, 0.05% of the exhaust gases respectively.

(a) Balance the combustion equation of C3H18 with 15% excess air, and fine the air-fuel ratio by mass.

(b) Estimate the total combustion air needed, carbon emission, and greenhouse gas CO2 generated from all gasoline engines of USA in Mton/year, and total sale of gasoline in USA in billion$/year.

(c) Estimate total emission of Pollutants: unburned HCs, CO, and NOx from mobile gasoline engines in USA per year.

Explain the following observations: Carbon has two important oxides which are both gases at room temperature. In contrast, silicon dioxide (silica) is a solid with a very high melting point.