Calculate the change in entropy of 144 g ice at -5 oC as it is heated to 0 oC , melted, heated to 100 oC, and then vaporized at that temperature. Suppose that the changes are brought by a heater that supplies energy at constant rate, and sketch a graph showing (a) the change in temperature of the system, (b) the enthalpy of the system, and (c) the entropy of the system as a function of time.

Part A: A saturated solution of magnesium fluoride , MgF2 , was prepared by dissolving solid MgF2 in water. The concentration of Mg2+ ion in the solution was found to be 1.18×10⁻³M . Calculate Ksp for MgF2 .

Part B: The value of Ksp for silver sulfate, Ag2SO4 , is 1.20×10−5 . Calculate the solubility of Ag2SO4 in grams per liter.

Propane is mixed with 20% excess air (propane air mixture is initially at 25 °C and 2.0 atm) and combusted at atmospheric pressure. It is assumed that the heat transfer between the chamber and the surroundings is negligible. In addition, you may assume that heat capacities of the gases are constant and that the reaction proceeds to 100% conversion. (30 points) a) Determine the flame temperature of the burner. b) Determine the flame temperature if 25% of the heat generated by combustion was lost through heat transfer to the surroundings? While doing the calculations you may assume that the heat capacities of the gases are constant. The heat capacities of the gases of interest are shown below. Gas Heat capacity Nitrogen 29.12 J/(mol*k) Oxygen 29.39 J/(mol*k) Propane 74.92 J/(mol*k) Carbon dioxide 37.14 J/(mol*k) Water 33.57 J/(mol*k)

1.How much water would be needed to completely dissolve 1.79 L of the gas at a pressure of 720 torrand a temperature of 21 ∘C? A gas has a Henry's law constant of 0.183 M/atm .

2.To what volume should you dilute 40.0 mL of a 4.45 M KI solution so that 23.5 mL of the diluted solution contains 3.15 g of KI?

3. The solvent for an organic reaction is prepared by mixing 70.0 mL of acetone (C3H6O) with 49.0 mLof ethyl acetate (C4H8O2). This mixture is stored at 25.0 ∘C. The vapor pressure and the densities for the two pure components at 25.0 ∘C are given in the following table. What is the vapor pressure of the stored mixture?

Suppose a 250.mL flask is filled with 2.0mol of O2 and 1.6mol of NO . The following reaction becomes possible: N2g+O2g =2NOg The equilibrium constant K for this reaction is 0.469 at the temperature of the flask. Calculate the equilibrium molarity of N2 . Round your answer to one decimal place.

Wrapping double-helical DNA around histone octamers condenses the DNA by a factor of 7. Higher order chromatin structures condense this DNA even further. During metaphase, the DNA is compacted by a factor of 1 × 10⁴. How many centimeters would the naked double-helical DNA from a 50 Mb chromosome stretch? (Note: Assume the DNA remains in the B-form, which has a rise per base pair of 0.34 nm.)

A. 0.017cm

B. 0.17 cm

C. 0.68 cm

D. 1.7 cm

E. 6.8 cm

What are “hallmarks” of chemical reactions, that is,how can you observe that a chemical reaction has taken place?

The degree of unsaturation, or index of hydrogen deficiency, is the number of pi bonds plus rings in a molecule.

Specify the degree of unsaturation (index of hydrogen deficiency) of the following formulas:

(a) C₂₅H₂₈

(b) C₉H₁₀O₂

(c) C₇H₇NO₄

(d) C₁₃H₁₄

(e) C₃H₅F

(f) C₈H₉NO₂

Both cyclopentadiene and cyclopentadienyl nion have same valence electrons and same 5-membered Carbon ring structure. However, cyclopentadiene adopts "envelope" shape with C on right tilted out of the plane of 4 Carbon atoms. The anion adopts flat structure. Further, the anion is far more stable chemically than cyclopentadiene. Speculate why this is so. Answer should consider both hybridization and resonance.

Mining companies use this reaction to obtain iron from iron ore : Fe2O3(s) + 3CO(g) = 2Fe(s) + 3CO2(g). The reaction of 167g Fe2O3 with 84.7g CO produces 76.5g Fe. Determine the theoretical yield. Determine the percent yield.

Calculate the pH and [S²⁻ ] in a 0.13 M H₂S solution. Assume K_a1 = 1.0 ✕ 10⁻⁷; K_a2 = 1.0 ✕ 10⁻¹⁹.

List a few terms that are unique for regulation of transcription in eukaryotic cells.

What enables PCR to amplify just one location (locus) in a person's genome as opposed to several loci scattered throughout the genome (what gives PCR its specificity)?

How can the carbon dioxide content of the atmosphere hundreds of years ago be determined today and what substances have been blamed for the loss of ozone in the atmosphere?