(2 pts) Estradiol is a potent female hormone. In 1934, Edward A. Doisy of Washington University extracted 3000 lb of hog ovaries to isolate a few milligrams of pure estradiol. Doisy burned 5.00 mg of this precious sample in oxygen and found that 14.54 mg of CO2 and 3.97 mg of H20 were generated. 3. (a) Determine the empirical formula of estradiol. (b) The molecular weight of estradiol was later determined to be 272. Determine the molecular formula of estradiol.

If MgCl2·H2O is the limiting reagent with a mole amount of 0.00189 mole. What is the theoretical yield of Mg(OH)2 (58.319 g mol-1) precipitate which will be formed?

In one experiment, 0.150 L of SnCl4 (d = 2.226 g/mL) was treated with 0.323 L of triethylaluminum (Al(C2H5)3); d = 0.835 g/mL).What is the theoretical yield in this experiment (mass of tetraethylstannane, Sn(C2H5)4)?

A 19.51 g sample of impure methylamine, which contains 72.58% (by mass) of CH;NH: , is reacted with 30.81 g of pure oxygen gas: 2.1 4CH, NH,(2) + 90,(8) - 4C0,(8) + 10H,0(?) + 2N;(8) 2.1.1 What is the percentage yield of this reaction if 5.54 g of nitrogen gas is collected? 2.1.2 In another experiment, this impure methylamine was used as follows: • An unknown mass of the impure compound is dissolved in enough water to make 500.0 m of solution. • 20 ml of this solution was transferred by pipette to a clean 250 ml volumetric flask and made up to the mark. • The molarity of the CH;NH; in the final solution was determined to be 0.103 M. Determine the mass of CH;NH; present in the original amount of impure compound used make this solution.

4. In this experiment, ethanol was selected to purify benzoin on Day 1. However, alcohols are inappropriate solvents for recrystallizing compounds containing carboxylic acids. One side reaction is "Esterification" that can occur by placing COOH and OH groups together upon heating. If 3.5 grams of Terephthalic acid and 3 mL methanol undergo esterification, (a) what is the limiting reagent? (b) Predict the grams of the two end products: dimethyl terephthalate and water assuming Esterification is driven to completion. Show calculations. Hint: you can find the grams of methanol through its density.

The reaction  3Ox(g) + M(g)  ⇋   4N(g)  has Kc = 67.10 Calculate Kc for the reaction: 2N(g) ⇋ 0.5 M(g)  + 1.5 Ox(g)

(2) 8. Write the balanced equation for the neutralization reaction between HI and Ba(OH)2 in aqueous solution. Include phases (physical states) in your equation. Use the arrow, not "=".

Regarding the combustion of gasoline, 2C8H18 (l) + 25O2 (g) --> 16CO2 (g) + 18H2O (g) How could you reduce carbon dioxide emissions?

Potassium permanganate reacts with oxalic acid (H2C2O4) in aqueous sulfuric acid according to the following reaction:   2 KMnO4(aq) + 5 H2C2O4(aq) + 3 H2SO4(aq) 2 MnSO4·H2O(s) + K2SO4(aq) + 10 CO2(g) + 6 H2O(l)   The reaction is run a second time and 8.74 g of MnSO4·H2O are obtained. What volume of carbon dioxide gas is collected at 1.01 bar and 23˚C? Answer in L with the correct number of significant figures; do not use scientific notation.

(3) A container holding NO2 and CO gas will lose NO2 gas via the reaction NO2 (g) + CO (g)  →  NO (g) + CO2 (g) A chemist measures the [NO2] over time and finds that plotting 1/[NO2 ]  versus time yields a straight line with a slope of 3.56×10-2 M-1·s-1.               If the container originally held 1.00 M NO2, what is the concentration of NO2 after 1.50 hour [NO2]1.5 hrs = ___________         How long will it take the [NO2] to drop to 20% of its initial concentration of 1.00 M?  T20% = __________