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Energetics and Thermodynamics

Entropy, Free Energy, Equilibrium

1. Define entropy and relate to probability of microstate formation. 2. Relate entropy and reaction spontaneity, Gibbs free energy and reaction spontaneity, and Gibbs free energy and the equilibrium constant of a reaction. 3. Calculate the entropy change within a system and determine absolute entropies. 4. In your own w

Specific Heats and Atomic Masses Using a Calorimeter

ChemLab program "specific heat" lab. Obtain 100 g shots of each: iron; copper & aluminum. Insert 150 ml of water at room temperature and heat to a final temperature of 100 degrees of celsius. Place in calorimeter and add 100 ml of water 20 degrees celsius. Measure specific heat for each metal and atomic weight. 100

Diels Alder Reactions of Cyclopentadiene

1) Why does cyclopentadiene dimerize so easily and rapidly to dicyclopentadiene? Please explain your answer. 2) Why must the distillation head temperature be maintained below 45oC suring the cracking of dicyclopentadiene? In other words, in the cracking of dicyclopentadiene, why is it necessary to distill the product very slowl

Exothermic Reaction: Shifting Reactions

Please help with the following physical chemistry problem. Consider the exothermic reaction 2NO(g) + Br2(g) <----> 2NOBr(g). What can you do to the reaction mixture to produce more NOBr? (Choose from the following choices:) (a) Decrease T (b) Remove Br2 (c) Add Br2 (d) Add NOBr (e) Decrease P (f) Remove NO (g) Incre

Net Ionic Reactions of Metal Chlorides

Add 2 mL each of silver nitrate [AgNO3], lead nitrate [Pb(NO3)2] and mercury(I) nitrate[Hg(NO3)2] to the test tube. The chlorides formed are: AgCl, PbCl2, Hg2Cl2. The mixture of the 3 above compounds once precipitated is added water and then heated to to 70C to get [Pb(NO3)2] to disolve it back into solution. PRECIPITATION B

15 Thermodynamics Problems (Delta G, Delta S, Delta H)

1) From the following Ho and So values predict which of reactions I, II, and III would be spontaneous at 300ºC. H (kJ) S(J/K) I -5.0 -15 II -10.0 +20 III -5.0 -30 A. I B. II C. III D. I and II E. II and III 2) From the following Ho and So values predict which of reactions I, II, and

Iron-Sulfur Combination

1) What kind of substance is iron-sulfur combination before heating? 2) Why is it necessary to heat the test tube in order for a chemical reaction to occur? 3) What kind of substance is iron-sulfur combination after heating? 4) The element sodium reacts explosively with water and the element chlorine is a yellow-green p

Calculating the amount of heat transferred

Consider the following reaction: CH3OH -->CO + 2H2 Delta H= 90.7 kJ Calculate the amount of heat transferred when 49.0g of CH3OH is decomposed by this reaction at constant pressure. For a given sample of CH3OH, the enthalpy change on reaction is 16.5kJ . How many grams of hydrogen gas are produced? What is the val

Why Did I Get Strange Results With My Distillation Unknown?

I performed a lab that dealt with finding the melting point of an unknown liquid. The possible liquids are Acetone (56.5 C) Methanol (65.0 C) Ethanol (78.5 C) Isopropanol (82.4 C) Isopropyl acetate (88.8 C) Water (100 C) Toleuene (110.6) Methyl isobutyl ketone (116.9) and 2-Methoxyethanol (124.0 C). I did the distallation a

Chemistry Questions

1) If a system loses 300 kJ of heat at the same time that it is doing 600 kJ of work, what is the change in the internal energy of the system? 2) Which of the following equations represents a reaction that provides the heat of formation of sodium hypochlorite (NaOCl)? 3) The heat of combustion for 1 mole of carbon to ca

Increase in Entropy

Thinking about entropy as disordered states, which of the following reactions would show an increase in entropy? Mark those in which entropy increases as TRUE. None of these reactions are balanced. H2 + O2 &#8594; H2O 1. True 2. False CaCO3 &#8594; CaO + CO2 1. True 2. False H2O(l) &#8594; H2O



the heat capacity of this calorimeter

When using a calorimeter to do detailed heat calculations, you must determine the heat capacity of the individual calorimeter you use as a calibration factor for later experiments. The fluid in a bomb calorimeter was heated for 568 seconds with a 15.00-watt heater. The temperature of the calorimeter fluid increased by 2.00 deg

Balanced Equation

The decomposition of solid potassium chlorate by heating yields solid potassium chloride and oxygen gas products. Write a balanced equation for this reaction.


General Information: The recrystallized adduct appeared as white, thin, long crystals weighing 0.3606 g and with a melting point of 123-126C. Based on the melting point ranges of the adduct sample, it was concluded that the unknown diene was alpha-phellandrene. DIRECTIONS: 1. DRAW the structure of the alpha-phellandr

Dimensional analysis

If an aluminum sphere has a mass of 23.01 grams and was heated to 137.0 Celsius and lowered into a cup containing 20.00 mL of water at 21.0 Celsius. The final temperature of the water and the sphere was 44.0 Celsius assuming no heat was loss calculate the specific heat of the aluminum in the sphere. C h2o =4.184J/g-0celsius


1.) If 596 J of heat are added to 29.6 g of water at 22.9 degrees Celsius in a coffee cup calorimeter, what will be the final temperature of the water? 2.) A 5.037 g piece of iron heated to 100. degrees Celsius is placed in a coffee cup calorimeter that initially contains 27.3 g of water at 21.2 degrees Celsius. If the final te

Element's Atomic Weight Based on Temperature

1. If a chemical cold pack weighing 28grams and at a temperature of -2C was left in a 25C room for 3 days, what would be the final temperature of the pack? 2. I have a lab experiment where I was used Styrofoam cup with deionized water for the purpose to measure temperature of the metal which previously was boiled for 5min. I

Crystallization Problems

2. Consider a crystallization of sulfanilamide in which 10 mL of hot 95% ethyl alcohol is added to 0.10g of impure sulfanilamide. After the solid has dissolved, the solution is cooled to room temperature and then placed in an ice-water bath. No crystals formed, even after scratching with a glass rod. Explain why this crystalliza

Hess' Law/thermochemistry

1. Use Hess's law and the thermochemical equations given below to calculate the standard enthalpy change for the reaction between C2H4 and F2. (see attached for formatted remainder) 2. (Hess's Law) Thermochemical tables tell us that the conversion of one mole of diamond to one mole of graphite is accompanied by the re

A bowl of oil and a bowl of water

A bowl of oil and a bowl of water have been placed under a heat lamp. The temperature of each was recorded every 5 minutes in the chart below. Using the data from the chart can you determine which absorbed more heat energy? Which has the highest specific heat? If you were to plot the data on a graph using 2 lines (one fo

Multiple choice questions on energy and temperature related reactions

If ΔG is negative, a reaction is spontaneous in the forward direction. A reaction that is not spontaneous at low temperature can become spontaneous at high temperature if ΔH is ________ and ΔS is ________. a. -, - b. +, + c. +, 0 d. -, + e. +, - Which one of the following statements is true about the equilibrium

Multiple choice questions on spontaneous reactions and maximum concentration

Calculate the maximum concentration (in M) of sulfide ions in a solution containing 0.181 M of lead ions. The Ksp for lead sulfide is 3.4 x 10-28. a. 1.9 x 10-27 b. 9.4 x 10-28 c. 1.5 x 10-26 d. 3.0 x 10-25 e. 3.4 x 10-28 A reaction that is spontaneous ___________. a. will proceed as written without outside interv

4 Dissolution/Solubility Questions

1. How much N2 can dissolve in water at 25'C if the N2 partial pressure is 585. Mm Hg? 2. Hexachlorophene is used in germicidal soalp. What is its molar mass if 0.640g of the compound, dissolved in 25.0 g of chloroform, produces a solution whose boiling point is 61.93 'C? 3. The enthalpy of solution of KClo3 in water is

Absolute entropy, free energy and spontaneity

1) Describe in detail the difference in absolute entropy values for the following pairs: a) C(s, graphite) and C(s, diamond) b) HCl(g) and HCl(aq) c) CH4(g) and CH3CH2CH2CH3(g) 2) a) Calculate the values of DeltaH° and DeltaS° for the following reaction at 25°C. b) Use the values from a to calculate DeltaG° for the

In the Decomposition Reaction of Gallium Chlorate...

5. In the decomposition reaction of gallium chlorate, 450 grams is heated, to produce oxygen and gallium chloride. Calculate the following: 1. Write the balanced equation for the reaction 2. Find the mole ratios of the reactants and products required to solve any stoichiometric problem 3. Find the mass in megagrams of ga

Aluminum Metal Volume

Alumminum metal melts at 660 degree Celsius and boils at 2450 degree C. Its density is 2.70 grams/cc. Calculate the following: the volume occupied by 15 milligrams of aluminum vapor at its boiling point and under a pressure of 1140 torr. the volume occupied by 100 kilograms of the metal at 25 C. If the specific heat ca