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.

Part A: By using the information given, calculate the energy produced by combustion of 1.5 L of gasoline.

Part B: By using the information given as well as data in Appendix C, calculate the energy produced by combustion of 1.5 L of ethanol. Consider that water is in the gaseous state.

A 40.0 mL of 2.00 M Fe^{3+ (aq)} solution are mixed with 60.0 mL of 3.00 M SCN^- (aq) solution. What is the equibrium concentratio of FeSCN²⁺ (aq), if the complex formation constanst is 189 for the reaction: Fe³⁺(aq) + SCN^- (aq) -----> FeSCN^{2+ (aq)} , Kf=189

A) 7mL of a 0.1M CaCl2 solution was diluted to a final volume of 150mL. Please determine the concentration of Cl- in this solution.

B) Explain why creating a standard curve is better than simply using the Beer-Lambert law directly. Assume that a value for molar absorptivity is readily available.

Quiz

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A sample of an unknown metal with a mass of 17.8 grams is heated in boiling water to a temperature of 98.0°C. The piece of metal is transferred to a sample of water with a mass of 15.0 grams at a temperature of 26.0°C. The metal cools to 30.5°C and the water warms up to 30.5°C. Calculate the specific heat of the metal. Use the table of specific heat values to identify the metal.

Options:

How many grams of dipotassium succinate trihydrate (K2C4H4O4�3H2O, MW = 248.32 g/mol) must be added to 540.0 mL of a 0.0306 M succinic acid solution to produce a pH of 5.969? Succinic acid has pKa values of 4.207 (pKa1) and 5.636 (pKa2).

The experiment is Determination of Acetic Acid in Vinegar. Please answer as many questions as you can.

What are primary and secondary standards? Give examples.

What is KHP and why was it used in this lab?

How is acetic acid formed in vinegar solution?

Why are pH indicators strongly colored even in solid state?

Why/how do pH indicators change colors in acid-base solutions?

Molar mass of acetic acid is often calculated or experimentally measured as 120 g/mol. Why?

Suggest another analytical method to determine the end point of an acid-base titration.

pH indicators are often weak acids or bases. Would adding indicators interfere with the determination of the endpoint for desired acid-base titration?

If a solution of NaOH is prepared and standardized today and left on the bench for a week, would you expect the pH of the solution change? Why? Ignore solvent (water) evaporation.

You had titrated unknown vinegar solution in flask against standard NaOH from burette using phenolphthalein indicator. If you had titrated standard NaOH solution in flask against unknown vinegar solution in burette using the same indicator, would it be easier or more difficult? Why?

H2A is a diprotic acid with Ka1+1.43 x 10^-3 and Ka2=2.01 x 10^-6. Consider the titration of 50.0mL of 0.300 M Na2A with 0.150 M HCL. Find the pH at the following volumes of HCl (a) 0.00ml (b) 50.0ml (c) 100.0ml (d) 175.0ml (e) 200.0ml (f)230.00ml

The experiment is Gravimetric Determination of Ca2+. Please answer as many questions as you can.

Write all the balanced equations involved in this experiment.

What is the purpose of urea? Can another base like NH4OH be used instead? Why?

Why was the reaction heated (to gentle boil) after adding urea?

What is the molarity of concentrated HCl (12 M)? How would you prepare 100 mL of O.1 M dilute HCl solution from it?

What is methyl red? Why was it used?

An aqueous solution of CaC2O4 would be basic, acidic or neutral? Why?

The product on the crucible was rinsed with cold water. What is the purpose of the rinse? What will happen if hot/warm was used?

Suggest a practical use of this lab (gravimetric determination of Ca) in real world?

What is water of hydration? How/Why does it become part of a crystalline inorganic molecule?

What happens when CaC2O4.H2O is heated at >500 0C for long time?

A 10.00 mL solution containing Cl- was treated with excess AgNO3 to precipitate 0.4368 g of AgCl. What was the molarity of Cl- in the unknown? FW of of AgCl is 143.321 g/mol.

You are given a solution and asked to analyze it for the cations Ag+, Ca2+, and Zn2+. You add HCl and a white precipitate forms. You filter out the solid and add H2SO4, and nothing appears to happen. You then add hydrogen sulfide (H2S), and a black precipitate forms. Which ions should you report as being present in your solution?

A 21.31 gram sample of cobalt is heated in the presence of excess fluorine. A metal fluoride is formed with a mass of 41.93 g. Determine the empirical formula of the metal fluoride

For a Michaelis-Menten reaction, k1=5*107 M-1S-1, k-1=2*104 S-1 and k2=4*102

S-1. Calculate the Km and Ks for this reaction. Does the substrate achieve equilibrium? How would inspection of the rate constant immediately have given you the same answer

A 50 mL solution of 0.02500 M maleic acid (ka1=1.3e-2, ka2=5.9e-7) was titrated with 0.100 M NaOH. Calculate the pH after the adiition of a) 0.00 mL, b) 9.00 mL, c) 12.50 mL, d) 20.00 mL, e) 25.00 mL, and f) 26.00 mL of NaOH

4) a) Describe, in detail, why metals are good conductors of electricity.

b) How are semiconductors different from “regular” metals, and how can this be controlled to allow for modern electronics.

What is the mole fraction of ethanol in a solution made by dissolving 29.2 g of ethanol, C₂H₅OH, in 53.6 g of water?