Explore BrainMass
Share

# Energetics and Thermodynamics

### 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.

### Thermodynamics

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

### Determining the temperature equation

What is the final temperature of a 52 gram glass of water at 2.0 C, if it absorbs 3.0 J heat? A. -2.0 B. -210 C. 150 D. 2.0 E. 75

### specific heat of aluminum

The specific heat of aluminum is 0.902 J g-1 C-1 at 25 C. How much heat, in kJ, does it take to raise the temperature of a 12.0 g chunk of aluminum from 15.5 C to 35.5 C? A. 0.216 kJ B. 0.0108 kJ C. 0.0180 kj D. 240 kJ E. 216 kJ

### 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?

### Thermodynamics

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

### WATER MASS

WHAT MASS OF WATER CAN BE HEATED FROM 5.5 DEGREES C TO 55.O DEGREES C BY 9.09 x 10^10 J of heat?

### 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

### Calorie and Specific Heat of Water

The calorie is an energy unit equal to about 4.2 joules. It is defined as the amount of heat required to raise one gram of water by one degree Celsius. An average person has a mass of around 68 kg. About how much energy would be required to raise an equal mass amount of water from room temperature (24 degrees celsius) to body

### 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.

### Reactions in Spectroscopy

1. Before spectroscopy was invented, Korner's absolute method was used to determine whether a disubstituted benzene derivative was the ortho, meta, or para isomer. Korner's method involves adding a third group (often a nitro group) and determining how many isomers are formed. A turn-of-the-century chemist isolated an aromat

### Diels-Alder

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

### 1st Law of Thermodynamics - Internal Energy, Heat and Work Problem

Calculate the change in internal energy (DU), heat (q) and work (w) when one kg of Ne is heated from 300 K to 400 K (a) at constant pressure (b) at constant volume (Assume an ideal gas)

### 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

### balanced reaction equations and net ionic equations

Write the balanced formulas for the reactants and predicted products for the chemical reactions that follow. Also include net ionic equations. a.) A solution of formic acid, HCOOH, is oxidized by an acidified solution of potassium dichromate. b.) Concentrated hydrochloric acid solution is added to solid manganese(IV) oxide a

### 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

### Thermochemistry - Heat of Reaction

1.) The specific heat of a solution is 4.18 J/(grams x degrees Celsius) and its density is 1.02 g/mL. The solution is formed by combining 20.0 mL of solution A with 30.0 mL of solution B, both initially at 21.4 degrees Celsius. The final temperature is 25.3 degrees Celsius. Calculate the heat of reaction. assuming no heat i

### Thermo-chemistry

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

### Solid sodium metal will reacts with liquid water to form sodium hydroxide

Solid sodium metal will reacts with liquid water to form sodium hydroxide [NaOH (aq)] and Hydrogen gas. The standard Enthalpy of this reaction is -368.4 kJ. How do I write the stoichiometric/balanced equation for this reaction? How much sodium metal and water would have to be used to produce enough heat to cause th

### Deciding Whether Axial or Equatorial OH is Attacked First

A steroid molecule is shown in the attachment. I have to explain which of the two is oxidised faster using Cr(VI) reagents. I've drawn the molecule in 3D and can say that the equatorial OH is more easily attacked than the axial one because the axial OH has axial interaction with Me causing steric hindrance to the incoming re

### 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

### Gas Laws & Air Composition

1. What can cause a can to collapse? 2.The pressure at sea level in New York City is 14.3lbs./in2. Is the pressure felt by the can while it is collapsing higher or lower than this value? 3. If you placed an un-opened soda can on a hot plate and heated the can to a very high temperature. All of a sudden, the can explodes. what

### 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?