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Energetics and Thermodynamics


For the following reaction, what is the enthalpy of cyclization per mole of actylene? 3C2H2 (g) --> C6H6 (l) ^H = -630 kJ A. 210 kJ/mol C2H2 B. -630 kJ/mol C2H2 C. 0 kJ/mol C2H2 D. -210 kJ/mol C2H2 E. -1890 kJ/mol C2H2


At 25 degrees C and constant pressure, carbon monoxide gas combines with oxygen gas to give carbon dioxide gas with the evolution of 10.1 kJ per gram of carbon monoxide consumed. What is the value of ^H for the balanced reaction? A. -566 kJ/MOL B. -283 kJ/MOL C. 283 kJ.MOL D. 141 kJ/MOL E. -141 kJ/MOL


What mass of oxygen gas, measured at 238 K and 3.51 atm, is required in ordered to release 6670 kJ of heat to the surroundings? CH4 + 2O2 --> CO2 + 2H20 ^H = 890.3 kJ A. 240 B. 6260 C. 0.574 D. 479 E. 7.49


Calculate the heat capacity of a sample of radiator coolant if a temperature rise from -5 degrees C to 142 degrees C requires 932J of heat? A. 0.158 J/C B. 1.37 x 10 to the power of 5 J/C C. 6.80 J/C D. 6.56 J/C E. 6.34 J/C

Specific Heat: Heat Absorbed by Copper

Copper clips are sometimes used as "heat sinks." How many grams of copper must be in contact with an electric component to absorb 10.0 J of heat and not let the temperature increase by more than 40 C? The specific heat of copper is 0.385 J/g K.


Calcium carbide (CaC2) reacts with water to form acetylene (C2H2), a gas used as a fuel in welding: CaC2 + 2H2O ==> C2H2 + Ca(OH)2 ^H = 128.0 kJ How many kilograms of CaC2 are consumed in a raction that releases 3.64 x 104 kJ of heat under these conditions? A. 1.82 x 10 to the power of 4 kg B. 284 jg C. -18.2 kg D

Heat applied to water and alcohol

Which of the following liquids has the highest specific heat capacity? water, alcohol, glycerine, or hexane. If you applied equal amounts of heat to equal masses of water and alcohol, which will stay closest to its initial temperature?


A burner on an electric range has a heat capacity of 345 J/K. What is the value of q (heat released) in kilojoules, as the burner cools from temperature of 467 degrees celsius to 23 degrees celsius. A. -153 kJ B. +153 kJ C. -531 kJ D. -431 kJ



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

Specific Heat: Temperature of the Coffee Cup After Adding Gold

A jeweler heats 60 g of gold (about 2 oz) almost to melting, 1000 degrees Celsius and drops it a cold cup of coffee to heat it up. If the cup has 200 ml of liquid in it (treat it as pure water) and is at 25 degrees Celsius before the hot gold is dropped in, estimate the temperature after the gold has been added. The specific hea

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

Using Hess's Laws in Various Equations

1.) Given the following data: Fe2O3(s) + 3CO(g) ---- 2Fe(s) + 3CO2(g) delta H = -23 kJ 3Fe2O3(s) + CO(g) ----- 2Fe3O4(s) + CO2(g) delta H = -39 kJ Fe3O4(s) + CO(g) ----- 3FeO(s) + CO2(g) delta H = +18 kJ Calculate delta H for the reaction FeO(s) + CO(g) ----- Fe(s) +CO2(g) 2.) At 298

heat of combustion for the reaction

1.) Calculate the heat of combustion for the reaction in which ethane combines with oxyen to give carbon dioxide and water vapor. C2H6 + 7/2 O2 ----- 2CO2 + 3H2O a.) 2C(s) + 3H2(g) ----- C2H6(g) delta H = -20.2 Kcal b.) C(s) + O2 (g) ------- CO2(g) delta H = -94.0 Kcal c.) H2(g) + 1/2 O2 ----- H2O(g) delt


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

Determination of the % and the number of moles of water in a hydrate

Two problems: 1. CuSO4.5H2O was heated such that the waters of hydration were driven off leaving the anhydrous salt. Calculate the percent change in mass as a result of dehydration. 2. When conducting the experiment to drive of the waters of hydration in alum to yield a less hydrous salt, Would it be more difficult to do

volume of ideal gas

1. A 410mL sample of fluorine gas is heated from 25C to 189C at constant pressure. What is its final volume. Please show all calculation. 2. A smple of carbon monoxide gas at atmospheric pressure (1atm) occupies 3.2 liters at 125C. How to calculate the new pr essure if the gas is compressed to 1.20 liters and the temperature

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