A certain weak base has a Kb of 7.60 × 10-7. What concentration of this base will produce a pH of 10.27?

(a) Consider the following two stage process:

                        Stage 1. The system absorbs 83 J of heat and during this process it had 44 J of work done on it.

                        Stage 2. The system absorbs 63 J of heat and during this process it does 27 J of work on the surroundings.

                        Calculate Q, w, and ΔE for the overall process

(b) A piston is compressed from a volume of 7.5 L to 2.2 L at a constant pressure of 1.5 atm. During this process, the system also absorbs 266 J of heat. Calculate ΔE for this process.

At 365 K, pure toluene and hexane have vapor pressures of 5.82*10⁴ Pa and 1.99*10⁵ Pa, respectively.

a. Calculate the mole fraction of hexane in the liquid mixture that boils at 365 K at a pressure of 1140 Torr.

b. Calculate the mole fraction of hexane in the vapor that is in equilibrium with the liquid of part (a)

Calculate the amount of ATP in kg that is turned over by a resting human every 24 hours. Assume that a typical human contains ~50g of ATP (Mr 505) and consumes ~8000 kJ of energy in food each day. The energy stored in the terminal anhydride bond of ATP under standard conditions is 30.6 kJmol-1. Assume also that the dietary energy is channeled through ATP with an energy transfer efficiency of ~50%. Express your answer to two significant figures, and don't forget units!

Suppose a solution contains 0.22 M Pb2 and 0.49 M Al3 . Calculate the pH range that would allow Al(OH)3 to precipitate but not Pb(OH)2. The Ksp values for Al(OH)3 and Pb(OH)2 can be found here.

SO3(g) + NO(g) NO2(g) + SO2(g) Kc was found to be 0.500 at a certain temperature. A reaction mixture is prepared in which 0.375 mol NO2 and 0.375 mol of SO2 are placed in a 4.00 L vessel. After the system reaches equilibrium what will be the equilibrium concentrations of all four gases? How do these equilibrium values compare to the values when 0.750 mol of SO₃ and 0.750 mol of NO are placed in a 8.00 L container and allowed to react.

1) What alkene(s) will be produced when each of the following alcohols is dehydrated?

2- propanol

2- butanol

2) Why is phosphoric acid preferred over sulfuric acid for dehydration of alcohols?

3) What measures should be taken if droplets of phosphoric acid are splashed in the eyes?

4) Give an example of a skeletal rearrangement during a dehydration experiment.

5) What is the purpose of adding anhydrous sodium sulfate to the dehydration product in experiment B?

1) What alkene(s) will be produced when each of the following alcohols is dehydrated?

Cyclohexanol

2-methylcyclopentanol

3-methylcyclopentanol

2,3-dimethyl-2-butanol

2) Illustrate the mechanism for the acid-catalyzed dehydration of cyclohexanol.

3) Illustrate the mechanism for the acid-catalyzed dehydration of 2-methylcyclohexanol. How many products are possible?

4) Write equations to illustrate the reaction of cyclohexene with KMnO₄?

5) Given the following data, calculate the theoretical yield and percentage yield of cyclohexene:

Cyclohexanol used: 20.0 mL

Cyclohexene obtained: 12.0 g

1) What alkene(s) will be produced when each of the following alcohols is dehydrated?

Cyclopentanol

2-methyl-2-butanol

2) What is the purpose of adding 2% sodium carbonate solution to the distillate in Experiment A?

3) If 8.0 grams of cyclohexanol are used in Experiment A, add 5.5 grams of cyclohexene are produced, what is the percentage yield?

4) The dehydration of 3,3-dimethyl-2-butanol yields three different products. Write equations to show how carbocation rearrangements explain two of the products.

5) List four reagents that may be used as catalysts in the dehydration of alkenes.

)? How would you electroplate a brass object with silver?

What is EPNS?

How could you use electrodeposition to measure the purity of a sample of copper sulfate?

How is this process used industrially to purify copper?

1. The pressure of 5.85 L of an ideal gas in a flexible container is decreased to one-third of its original pressure, and its absolute temperature is decreased by one-half. What is the final volume of the gas?

2. A piece of sodium metal reacts completely with water as follows:

2Na(s) + 2H₂O(l) → 2NaOH(aq) + H₂(g)

The hydrogen gas generated is collected over water at 27.0°C. The volume of the gas is 175 mL measured at 0.969 atm. Calculate the number of grams of sodium used in the reaction. (The vapor pressure of water at 27.0°C = 0.0352 atm.)

How many milliliters of 0.500 M KOH should be added to 2.38 g of oxalic acid (molecular weight: 90.03, pKa1=1.46; pKa2=4.40) to give a pH of 4.50 when diluted to 250 mL?

Acid deposition is the transfer of acids in the atmosphere to Earth\'s surface through precipitation, fog, and aerosols. The presence of air pollutants, such as sulfur oxides (SOx) and nitrogen oxides (NOx), has caused acid deposition to occur. What are some of the results of acid deposition? Select all that apply.

corrosion of marble monuments

lower acidity levels in surface waters

greater soil nutrients

forest degradation

increased deaths from asthma

The role of catalysts is critical in many chemical reactions. They have great consequence in the fields of medicine and pharmacology. On the basis of your research, respond to the following: Identify the two important classes of catalysts. Choose a catalyst that exists in the human body. Explain its importance and how it works. Analyze the chemical reactions that take place when a biological catalyst combines with a reactant (substrate) to form an unstable intermediate.

A titration experiment is done with 1.37E-2 M NaOH to determine the acid concentration in 0.631 L of an unknown acidic solution. It was found that to reach the equivalence point 12.3 mL of strong base was needed. What was the pH of the original acidic solution?