Explore BrainMass

Energetics and Thermodynamics

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

Frequency, Wavelength, and the electromagnetic spectrum

Please show how to solve: 1) A function of wavelength (the intensity of radiation emitted by a solid) has its peak at (2.877 x 10^-3)/ (t+273.15). t represents the temp in degrees C and the peak wavelength is in m. Determine the frequency in Hz corresponding to the peak wavelength and identify the region of electromagnetic s

Thermodynamics, Properties of Pure Substances

Superheated water vapor at 180psia and 500 degree F is allowed to cool at a constant volume until the temperature drops to 250 degrees F. At final state, determine (a) the pressure, (b) the quality, and (c) the enthalpy. Also, show the process on a P-v diagram with respect to saturation lines.

Boiling Point of a Solution Given Density and Molecular Weight

An environmentally concerned graduate student uses the more earth-friendly anti-freeze, propylene glycol (C3H8O2, density = 1.038). The final composition in her car's radiator is 30% (volume/volume) ethylene glycol (C2H6O2, density 1.114 g/ml) and 20% (V/V) propylene glycol in water. At what temperature will her engine overheat?

The heat of evaporation of water is 540 cal/g

The heat of evaporation of water is 540 cal/g. the specific heat is 0.48 cal/g-c. What will final temperature be if 1020 calories are added to 10 g of water originally 100 degree C?

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

Heat Required to Convert Ethanol to its Vapor Phase

Ethanol, C2H5OH, melts at -114 degrees C and boils at 78 degreesC. The enthalpy of fusion of ethanol is 5.02kj/mol and the enthalpy of vaporization is 38.56kj/mol. The specific heats of solid and liquid ethanol are 0.97J/g-K and 2.3J/g-K respectively. How much heat is required to convert 75.0g of ethanol at -120 degreesC to t

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

Reverse process activation energy

3.) Show the reaction coordinate diagram (energy diagram) for the process in which the energy change of the reaction is -60 kJ, and the activation energy is 30 kJ. What is the reverse process activation energy?

Enthalpy of Calorimeter

What is the final temperature of a calorimeter in which 5.6g of copper at 354 K is put into 56.8 g of water at 22.4 degrees centigrade?

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

Total Heat Calculation

From the data listed, calculate the total heat, in Joules, to convert 10.0 g of liquid ethanol at 55.0 C to gaseous ethanol at 95.5 C.

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

Various Calculations of Thermodynamics

1. At 25 degees C, (triange)H(little o) for the combustion of liquid octane, C8H18(l) to form CO2(g) and H2O(l) is -5471kJ/mol. Calculate (triangle)E(little o) for this reaction at 25 degrees C. 2. The molar heat of vaporization of benzene, C6H6, at 1 atm is 30.8 kJ/mol. The boiling point of benzene at 1 atm is 78.3 degree C.

Sign of Delta S

1. Predict the sign of delta S for the following reaction. Please explain the reason for your prediction. HgS(s) + O2(g) yields Hg(l) + SO2(g)

Enthalpy Change

Hydrogen peroxide decomposes according to the following thermochemical reaction: H2O2(l) --> H2O(l) + 1/2 O2(g); DH = -98.2 kJ Calculate the change in enthalpy, DH, when 1.00 g of hydrogen peroxide decomposes.