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Newton's Law of Cooling: Differential Equations

Two identical cups of coffee are poured at the same time into two identical cups. Into one cup is added a teaspoon of cream at Tc which is less than room temperature. !0 minutes later the temperature of this coffee is measured. The second cup is allowed to sit for 10 minutes and then the cream, at Tc, is added to this cup and

At combustion temperatures, the equilibrium constant

At combustion temperatures, the equilibrium constant for the reaction N2 + O2 -> 2NO is about 7.0E-14. Calculate the concentration(atm) of nitric oxide that is in equilibrium with atmospheric levels of nitrogen and oxygen.

Calculate Time to Form a Junction: Example Problem

Given a background p-type diffusion of 10^6 donor atoms/cm^3 and a surface concentration N = 10^21 impurity atoms/cm^3 (assume a 1 cm^2 area). Find the time it takes to form a junction at depth of 1um at a temperature 1050 degrees C. D = 10^-13 cm^2/s


Problem 1: 200 grams of boiling water and 100 grams of ice-cold liquid water are combined in a sealed thermos bottle. (a) What is the final (equilibrium) temperature in the thermos? Hints:C = specific heat of water = 4.186 J/gm0K (b) What is the change in entropy for the parts (hot water and cold water) of the s

Change of State, calculate the heat of vaporization of water.

In an experiment, a certain amount of steam was allowed to mix with a known mass of cold water whose temperature is known. The change in temperature was noted. From the data obtained, calculate the heat of vaporization of water. Weight of calorimeter = 100.0g Specific heat of calorimeter = 0.1cal/g°C Mass of water =

Speed of Sound of approaching train in the rail and in the air

Have you ever listened for an approaching train by kneeling next to a railroad track and putting your ear to the rail? Young's modulus for steel is Y = 2.00 x 1011 N/m2, and the density of steel is = 7860 kg/m3. On a day when the temperature is 24.1 oC, how many times greater is the speed of sound in the rail than in the air?

Physics: Thermal Expansion problems

The answers are provided. Please show the calculations. 1. The coefficient of linear expansion of steel is 1 x 10-5/°C. How much expansion should engineers anticipate in a 2,000-ft steel bridge if it undergoes a change in temperature from 0°C to 30°C? Answer : 0.6ft 2. A 2m-long aluminum pipe at 27°C is heated until

Kinetics and Thermodynamics of Reactions

1. Under which temperature conditions will the following reaction be spontaneous? A(aq)+B(aq) C(s)+D(aq) ΔH°=-34.0kJ/mol ΔS° = -57.0 J/mol•K A) above 273°C B) below 323°C C) above 552°C D) below 705°C E) At all temperatures. 2. What is the value of ΔG° (in kJ/mol) for this reaction at 25°C? A (g) B

Dissolution of Urea

Could you please show me in detail how to do this? We were asked to repeat the procedure 3 times using different amounts of urea. Additionally, we were asked the minimum and maximum temperatures. My answers are: Adding 2 grams of urea and 50 mL of water: Initial temperature = 21.00 degrees C minimum temperature = 18.99

Deformation of block of wood when one surface is heated

See the attached diagram. A block of wood that is 3 inches wide x 6 inches long x .380 inches thick is fixed/anchored to a structure. The top surface of the wood block is heated to 300 degrees C. The bottom surface is cooled to an undetermined temperature. The differential in temperature causes the top surface to expand

Pressure, Volume, and Temperature are given to find moles

A tank of volume 0.5 m^3 contains oxygen at a pressure of 1.5E6 Pa and a temperature of 20 C. Assume that the oxygen behaves like an ideal gas. a. How many kilomoles of oxygen are in the tank? b. How many kilograms? c. Find the pressure if the temperature i increased to 500 C. d. At a temperature of 20 C, how many kil

Physics Questions: Temperature

1) An aluminum plate has a length of 0.12 m and a width of 0.10 m at 25 degrees Celsius. The plate is uniformly heated to 225 degrees Celsius. If the linear expansion coefficient for aluminum is 2.3 x 10^-5.Cdegrees, what is the change in the area of the plate as a result of the increase in temperature [note: 3x 10^-3 m^2 is 0.0

Thermal Expansion in Solids

The brass bar and the aluminum bar are attached to and immovable wall. At 28 degrees Celsius the air gap between the rod is 1.3x10^-3 m. The brass bar is located on the left with 2.0m in length and the aluminum bar is on the right with 1.0m in length with a gap in between the two bars. At what temperature will the gap be closed?

Relationship between Resistance and Temperature.

Please help with the following thermodynamics problem. The current, passing through an incandescent light bulb, becomes lower than the initial value, some moments later after it is switched on. Why? a) Change in drift velocity b) Change in Electrostatic Potential (Potential drop across the conductor) c) Chang

Physics: Pyrex glassware resistence to temp changes; refrigerator door left open

Please help with the following problem. 3. Pyrex glassware is noted for its ability to withstand sudden temperature changes without breaking. Explain how its coefficient of linear expansion contributes to this ability. 4. The door of a refrigerator is left open. Assuming the refrigerator is in a closed room, will the air

Problems on Pascal's law, pressure etc.

1). Here is a demonstration Pascal used to show the importance of a fluid's pressure on the fluid's depth. (See attachment) An oak barrel with a lid of area 0.20 m^2 is filled with water. A long, thin tube of cross sectional area 5.00 10^-5 m^2 is inserted into a hole at the center of the lid, and water is poured into t

Temperatures of a block of ice after heat is added

A 1.1 kg block of ice is initially at a temperature of -5°C. (a) If 4.8x10^5 J of heat are added to the ice, what is the final temperature of the system? ________°C (b) Suppose the amount of heat added to the ice block is increased by a factor of 5.2. By what factor must the mass of the ice be increased if the system

Characteristic Properties - Melting and Boiling Points

Procedure 1 1. Take a Constant Temperature Bath from the Tools shelf and place it on the workbench. 2. Open the Properties window and click on the Constant Temperature Bath. Set the bath temperature to "dry ice". 3. Take a clean test tube from the Glassware shelf and place it on the workbench. 4. Fill the test tube

A C++ console program that will read input data from a text file and performs simple meteoroligical calculations - finding greatest temperature deviation and wind average. Makes use of structures and arrays.

You are developing a database of measured meteoroligical data for use in weather and climate research. Define a structure type measured_data_t with components: site_id( a 4 digit integer), wind_speed, day_of_month, and temperature. Write a program that inputs measured_data_t records and determines the site with the greatest va

Tempature and Heat questions are examined.

A copper vat is 44m long at 20 degrees Celcius. How long will it be when filled at boiling water (at one atmosphere of presure) This is needed at the nearest three decimal places. an aluminum wing on a plane is 35.5m long when the temperature is 20 degrees celcius. At what temperature would the wing be at 0.06m shorter. Th

Heat Flow - Coupled systems and reversal of processes

Each of two bodies has a heat capacity given, in the temperature range of interest, by C = A + BT • Where A = 8.0 J/K and B = 0.02 J/K2. If the two bodies are initially at temperatures: T10 = 400.0 K and T20 = 200.0 K, and if they are brought into thermal contact, what is the final temperature and what is the change in entr

Pressure, Temperature and Absolute Zero Calculations

Procedure 1. Take a gas piston from the Glassware shelf and place it on the workbench. 2. Take a balance from the Tools shelf and drop it directly onto the gas piston. Record the mass of the empty piston. Mass of empty piston 111.420 g 3. Select one of the gases from the Chemicals shelf and fill the gas piston with 100

Heat and Temperature: Method of mixture.

A 0.200 kg piece of aluminum that has a temperature of -155 degrees Celsius is added to 1.5 kg of water that has a temperature of 3.0 degrees Celsius. At equilibrium the temperature is 0.0 degrees Celsius. Ignoring the container and assuming that the heat exchanged with the surroundings is negligible, determine the mass of wat

Temperature of a Brass Bar and Aluminum Bar

Brass bar and aluminum bar fastened to two removable walls their is a air gap between them. at a certain temperature the gap measures a certain amount. a) what temperature will cause the gap to close?

Brass and Aluminum Bars: Closing the Gap

Brass bar and aluminum bar fastened to two removable walls their is a air gap between them. At a certain temperature the gap measures a certain amount. What temperature will cause the gap to close?

Line Broadening to Measure Homogeneous Width

More line broadening: Figure 6.2 shows data from measurements of the homogeneous line width of the D_1 (6p^2 P_1/2 --> 6s^2 S_1/2) and D_2 (6p^2 P_3/2 --> 6s^2 S_1/2) transitions in Cs at 894 and 852 nm respectively. In addition to the homogeneous broadening, in homogeneous broadening is caused by the thermal motion of the a

Resistance of Wires and Temperature

1.) What is the resistance of a Nichrome wire at 0.0 degrees C if its resistance is 140.00ohms at 11.5 degrees C? Express your answer using four significant figures. 2.) What is the resistance of a carbon rod at 25.8 degrees C if its resistance is 0.0120ohms at 0.0 degrees C?

Van der Waals constant and compression factor

A certain gas obeys the van der Waals equation with a = 0.76 (m^6) Pa/(mol^2). Its volume is found to be 4.00 x 10-4 (m^3)/mol at 288 K and 4.0 MPa. From this information, calculate the van der Waals constant b. What is the compression factor for this gas at the prevailing temperature and pressure?

Nursing Research to determine the effects of three cooling blanket temperatures

I will need to develop a study (as an advance practice nurse in an ICU) to determine the effects of three cooling blanket temperatures on: 1) time to cool 2) shivering and 3) self-perceived discomfort in adults with fever In your response: A. Identify an appropriate study design B. Diagram the study design C. Discuss t