Calculate D_rxnH

Part A

A balloon is floating around outside your window. The temperature outside is 27 ∘C , and the air pressure is 0.800 atm . Your neighbor, who released the balloon, tells you that he filled it with 3.50 moles of gas. What is the volume of gas inside this balloon?

Part B

A 12.0 L gas cylinder is filled with 7.60 moles of gas. The tank is stored at 31 ∘C . What is the pressure in the tank?

Part C

A 140. L kiln is used for vitrifying ceramics. It is currently operating at 1095 ∘C , and the pressure is 1.000 atm . How many moles of air molecules are within the confines of the kiln?

Define the equivalence point of an acid-base titration. Describe it for a weak acid-strong base titration (will the pH be >,<, or = 7).

Hydrogen gas, H2, reacts with nitrogen gas, N2, to form ammonia gas, NH3, according to the equation

3H2(g)+N2(g)--> 2NH3(g)

a.) How many grams of NH3 can be produced from 3.45mol of N2 and excess H2? Express your answer numerically in grams.

b.) How many grams of H2 are needed to produce 14.79 g of NH3?

c.) How many molecules (not moles) of NH3 are produced from 5.23×10⁻⁴ g of H2?

Water has a number of unique properties that sets it apart from other substances, sometimes called the “anomalies of water.” The most commonly recognized anomalies are: The match between the range of temperatures of liquid water and the “normal” temperatures on earth. Water’s high specific heat (and therefore water’s good coolant/”temperature buffer” properties). Water’s “universal solvent” properties (ability to dissolve a wide range of different substances). The lower density of ice vs. liquid water (the fact that water “expands when freezing”). Water’s high cohesion and high surface tension (its property of “sticking together” strongly, forming droplets and making water surface resist being stretched or broken). Pick 1 of these properties and learn more about how it canbe explained from the viewpoint of attraction forces between molecules and/orother physical properties of water, as well as the significance of these properties for life on earth. You can use the textbook and any other online materials, though you may want to review the articles in the Additional Materials folder of this module/week. Based on the information you have learned, write a thread about 1 of the anomalies, referencing your sources and address the following points: How is the anomaly explained from the viewpoint of the properties of water molecules (if it is relatively clear)? What is the significance of these properties for life on earth? Or, what is the significance for the functioning of the human body? How does this property of water reflect (or play into) God’s design of earth and life?

Calculate the solubulity and molar solubility of CaF2 at 25 degrees celsius in a solution of 0.0100 M NaF. Ksp(CaF2)= 3.9e-11

As inventor claims that there is a steady flow device which can process an ideal gas at constant temperature and pressure and produce useful work. Would you believe this claim??

1. Express 2.5M NaCl as a percent solution.

What is the molar concentration of a 10% NaCl solution?

2. from a 1M Tris solution, how is a 400ml of 0.2M Tris is prepared?

3. What is the molarity of a solution of sucrose that has a density of 1.24 g/ml and a molecular weight of 342.3 g/mol.

4. Forty micoliters of a stock solution of RNA is diluted with water to give a final volume of 1000 microliters. The diluted sample has an absorbance at 260nm of 0.142. What is the concentration of the concerntration of the RNA stock solution in micro grams/milliliter.

5. from a small culture, you have purified the DNA of a rocombinant plasmid. You have resuspended the DNA in a volume of 50 microliter. You dilute 20 of the purified DNA sample into a total volume of 1000 microliter distilled water. You measre the absorbance of this diluted sample at 260 nm and 280 nm and obtain the following readings.

A260=0.550

A280=0.324

a. What is the DNA concentration of the 50microliter plasmid prep?

b. How much total DNA was purified by the plasmid preparation?

c. What is the A260/A280 ratio of the purified DNA?

a) Balance the following molecular equations for these reactions.
b) write the ionic equation for the reactions.
c)write the net ionic equation for the reactions.

a) La2(CO3)3 (s) + HCl (aq) --> LaCl3 (aq) + CO2 (g) + H2O (l)

b) K2S2 (aq) + Bi(NO3)3 --> Bi2(S2)3 (s) + KNO3 (aq)

Consider the following Galvanic Cell : Al (s) | Al ⁺³ (0.010M) || Fe ⁺²(0.10M) | Fe(s) where,

Al⁺³ + 3e > Al(s) E = -1.662 V

Fe⁺² + 2e > Fe (s) E -.440 V

A. What is potential of the above voltaic cell at 25C ?
B.) Calculate Delta G of the above cell at 25C ?

Calculate [OH ^-] and pH for each of the following solutions.



(a) 0.0062 M LiOH

(b) 0.0431 g of LiOH in 480.0 mL of solution

(c) 13.7 mL of 0.00220 M Sr(OH)₂ diluted to 600 mL

(d) A solution formed by mixing 15.0 mL of 0.000560 M Sr(OH)₂ with 89.0 mL of 1.2 x 10^-3 M LiOH

6. (10 pts) Balance the following reaction in basic solution (add water or OH as needed). Clearly show your work.

Al(s) + S(s) -----> Al(OH)3 (s) + HS-(aq)

In the upper atmosphere, ozone is produced from oxygen gas in the following reaction. 3O2(g) → 2O3(g) Calculate ΔGo for this reaction. Enter your answer in kJ and give 3 significant figures.

Calculate ΔHo for ozone formation. (Enter your answer in kJ and give 3 significant figures).

Calculate ΔSo for ozone formation. (Enter your answer in J/K and give 3 significant figures).

Assume an atmosphere where p(O2) = 0.025 atm, and where T = 298 K. Below what pressure of O3 will ozone production be spontaneous? (Enter your answer in atm).