Suppose that an 85.0gram laboratory animal ingested 10.0mg of a substance that contained 2.50% by mass Pu-239, an alpha emitter with a half-life of 24,110 years.

1) What is the animal's initial radiation exposure in Curies?

2) If all of the energy from the emitted alpha particles is absorbed by the animal's tissues, and if the energy of each emission is 7.77x10E-12J what is the dose in rads to the animal in the first 4.5 hours following the ingestion of the radioactive material?

3) Assuming a biological effectiveness factor of 20, what is the 4.5-hour dose in rems?

Dry ice is solid carbon dioxide. Instead of melting, solid carbon dioxide sublimes according to the following equation: CO2(s)→CO2(g). When dry ice is added to warm water, heat from the water causes the dry ice to sublime more quickly. The evaporating carbon dioxide produces a dense fog often used to create special effects. In a simple dry ice fog machine, dry ice is added to warm water in a Styrofoam cooler. The dry ice produces fog until it evaporates away, or until the water gets too cold to sublime the dry ice quickly enough. Suppose that a small Styrofoam cooler holds 15.0 liters of water heated to 83 ∘C.

Use standard enthalpies of formation to calculate the change in enthalpy for dry ice sublimation. (The ΔH∘f for CO2(s) is - 427.4kJ/mol). Express your answer using three significant figures.

Calculate the mass of dry ice that should be added to the water so that the dry ice completely sublimes away when the water reaches 11 ∘C. Assume no heat loss to the surroundings. Express your answer using two significant figures.

K_a for Benzoic acid (a monoprotic acid) is K_a = 6.5*10^-5. Calculate the pH after addition of 23.0, 35.0, 46.0, and 49.0 mL of 0.100M NaOH to 46.0 mL of 0.100M Benzoic acid

The automobile fuel called E85 consists of 85% ethanol and 15% gasoline. E85 can be used in so-called flex-fuel vehicles (FFVs), which can use gasoline, ethanol, or a mix as fuels. Assume that gasoline consists of a mixture of octanes (different isomers of C8H18 ), that the average heat of combustion of C8H18(l) is 5400 kJ/mol , and that gasoline has an average density of 0.70 g/mL . The density of ethanol is 0.79 g/mL .

A. How many gallons of E85 would be needed to provide the same energy as 40 gal of gasoline?

Express your answer to two significant figures and include the appropriate units.

B.

If gasoline costs $ 3.88 per gallon in the United States, what is the break-even price per gallon of E85 if the same amount of energy is to be delivered?

Express your answer using three significant figures.

Describe the way(s) in which a homotropic allosteric effector could affect a substrate activity curve.

Calculations Involving a Limiting Reactant

Question 16.

This question has multiple parts. Work all the parts to get the most points.

a. "Smelling salts," which are used to revive someone who has fainted, typically contain ammonium carbonate, (NH₄)₂CO₃. Ammonium carbonate decomposes readily to form ammonia, carbon dioxide, and water. The strong odor of the ammonia usually restores consciousness in the person who has fainted. The unbalanced equation is

(NH₄)₂CO₃(s) → NH₃(g) + CO₂(g) + H₂O(g)

Calculate the mass of ammonia gas that is produced if 2.25 g of ammonium carbonate decomposes completely.

___________________ g NH3

b. Sulfurous acid is unstable in aqueous solution and gradually decomposes to water and sulfur dioxide gas (which explains the choking odor associated with sulfurous acid solutions).

H₂SO₃(aq) → H₂O(l) + SO₂(g)

If 6.50 g of sulfurous acid undergoes this reaction, what mass of sulfur dioxide is released?

_____________________ g SO2

c. For the following unbalanced chemical equation, suppose that exactly 1.75 g of each reactant is taken. Determine which reactant is limiting, and calculate what mass of CO₂ is expected (assuming that the limiting reactant is completely consumed).

CS₂(l) + O₂(g) → CO₂(g) + SO₂(g)

Limiting reactant is _______________________

__________________ g CO2

d.   Lead(II) carbonate, also called "white lead," was formerly used as a pigment in white paints. However, because of its toxicity, lead can no longer be used in paints intended for residential homes. Lead(II) carbonate is prepared industrially by reaction of aqueous lead(II) acetate with carbon dioxide gas. The unbalanced equation is

Pb(C₂H₃O₂)₂(aq) + H₂O(l) + CO₂(g) →

PbCO₃(s) + 2HC₂H₃O₂(aq)

Suppose an aqueous solution containing 1.35 g of lead(II) acetate is treated with 5.95 g of carbon dioxide. Calculate the theoretical yield of lead carbonate.

_______________________ g PbCO3

You probably heard about deep-sea diving with suits in which the divers breath fluids. The movie "The Abyss" portrays it wonderfully. The diver is put into a diving suit which is filled with an oxygen-rich fluid that he can breath. After some disorientation, the diver starts to breath the fluid and can dive to depths of up to hunderds or thousands of meters. (Don't you love sci-fi?)

Still, one thing puzzles me. There's more air in a body than just in your lungs. What about all the air in the Eustachian tubes in your ears? Won't your eardrums rip when the pressure changes that much and there's still air in those tubes? And what about the gasses in your bowls or stomache? Will they dissolve or will you also need some sort of an enema when you dive to those depths? Is it vital to burp so that all the gasses in your stomache are gone? And are there any other air bubbles inside a body that usually are harmless but could seriously injure someone at those depths?

The equilibrium constant Kc for the decomposition of phosgene, COCl2, is 4.63 × 10−3 at 527°C: COCl2(g) ⇆ CO(g) + Cl2(g) Calculate the equilibrium partial pressure of all the components, starting with pure phosgene at 0.760 atm.

Calculate the percentage change in the equilibrium constant Kx of the reaction H2CO(g) to CO(g) + H2(g) when the total pressure is increased from 1.0 bar to 2.0 bar at constant temperature

A 0.2000M pyridine (Kb=1.7*10^-9) solution with initial volume 10.000ml is titrated with 2.500*10^-1 M HCL. what is the pH after the addition of :

a.) 2.00ml of HCL solution

b.) 6.00ml of HCL solution

c.)8.00ml of HCL solution

d.)10.00ml of HCL solution

A solution is made by dissolving 0.717 mol of nonelectrolyte solute in 817 g of benzene. Calculate the freezing point, Tf, and boiling point, Tb, of the solution.

describe the effects of

mixed inhibition

Substrate inhibition

Product inhibition

Mechanism based/suicide inhibitors

Covalent intermediates

Ping Pong Mechanisms

Burst Kinetics

Allosteric Inhibitors

Specify which of the following statements regarding dehydration lab (dehydration of 2-methylcyclohexanol) are True or False?

a) Both product alkenes will have an equal affinity for the GC column material.

b) More 1-methylcyclohexene is formed because it involves a less stable carbocation intermediate, compared to the other possibility

c) This reaction is not regioselective.

d) A tertiary alcohol would not undergo this dehydration.

e) Distilling at too high a temperature will result in contamination of the products.

25.00 mL 0.100 M CH3NH2 is titrated with 0.100 M HCl. Calculate the pH of this the titration solution after the addition of a) 12.5 mL and b) 25.00 mL of the titrant has been added. Based on these pH values, select an appropriate indicator for the titration from table at the end of lecture notes for Chapter 16.

Two sets of measurements of ethanol concentration in a sample of vodka were made using the same instrument, but on two different days.

On the first day, a standard deviation of s₁ = 9 ppm was found,

and on the next day s₂ = 2 ppm.

Both datasets comprised 6 measurements.

Can the two datasets be combined, or is there is a significant difference at 95% confidence between the datasets, and should we discard one of them?

Hint: Begin by defining the null hypothesis, H₀: s₁² = s₂², and the alternate hypothesis, H_A: s₁² ≠ s₂².