Transmission of heat Questions and Answers

13. The mass of an object is 229 g- The object requires 20.0J to raise its temperature by 10.0° C. What is the specific heat of the object? 4,580,000 J/kg. K 2000 J/kg-K 0.00110 J/kg . K 8.73 J/kg-K

A sphere has radius 0.30 m, surface emissivity 0.48, and temperature 600 K. Surrounding the sphere is a concentric spherical shell. The inner surface of the shell has radius 0.90 m, emissivity 1.00, and temperature 400 K. At what net rate and direction is heat radiated across the space between the sphere and the shell? The Stefan-Boltzmann constant is 5.67 x 10-8 W/(m². K4). 6.5 kW, inward 8.3 kW, outward 4.0 kW, outward 10.8 kW, inward 18.8 kW, outward

A gas at 100° C fills volume Vo. Part A If the pressure is held constant, by what factor does the volume change if the Celsius temperature is doubled? ▾ Part B If the pressure is held constant, by what factor does the volume change if the Kelvin temperature is doubled?

A X means your answer is close but wrong (do not round off at all unless stated). Specific Heat: (a) How much heat must be removed from a 264 g block of steel to lower its temperature from 80°C to 12°C?

The specific heat c of a solid at low shows temperature dependence according to the relation c = DT3 where D is a constant and I is the temperature in kelvin. A piece of this solid of mass m kg is taken and its temperature is raised from 20K to 30K. The amount of the heat required in the process in energy units is 5 x 10¹ Dm (33/4) × 10¹ Dm (65/4) × 10¹ Dm (5/4) × 104 Dm

In a container of negligible mass 140g of ice initially at -15°C is added to 200g of water that has a temperature of 40°C. If no heat is lost to the surroundings, what is the final temperature of system in °C ?

A change in the free energy of a system at constant temperature and pressure will be: At constant temperature and pressure Asys G < 0(spontaneous) Asys G = 0(equilibrium) Asys G> 0(non - spontaneous) The free energy for a reaction having

5 g of water at 30°C and 5 g of ice at -20°C are mixed together in a calorimeter. Find the final temperature of the mixture. Assume water equivalent of calorimeter to be negligible, specific heats of ice and water are 0.5 and 1cal/g°C, and latent heat of ice is 80 cal/g.

A substance registers a temperature change from 20.5 °C to 40.2 °C. To what incremental temperature change does this correspond? HINT: Change each to Kelvin first then find the temperature change. (K = °C + 273.15) Round to the tenth place.

Four ice cubes are dropped in a soda at 15°C and mass of soda is 0.30 kg. The ice is at 0°C and each cube has a mass of 5.0 g. Assuming that no heat is lost to the surroundings and specific heat of soda is is same as water (4.184 kJ/kg . K), find the final temperature when all ice has melted. Water's heat of fusion is 334 kJ/kg.

Find the net rate of heat loss by radiation from a skier standing in the shade, given the following. She is completely clothed in white (head to foot, including a ski mask), the clothes have an emissivity of 0.200 and a surface temperature of 11.0°C, the surroundings are at -11.3°C, and her surface area is 1.57 m².

The ice maker inside a refrigerator makes ice cubes at 0.0°C from water that is at 13.7°C when it first enters the ice maker. If this machine is rated at 244 W and has a 3.86 coefficient of performance, what is the maximum amount of ice it can produce in a 24 hour period without any interruption or stoppage? Assume that the ice maker works just like a refrigerator. The specific heat of water is 4184 J/(kg °C), and the latent heat of fusion of ice is 33.4 x 104 J/kg.

Question 9 Points 2 Complete the equation: 2 Cu (s) + O₂ (g) →___(s). Cu₂O CuO CUO₂ Cu₂O2

Heat capacity is defined as: the transfer of energy across the boundary of a system due to a temperature difference between the system and its surroundings. the heat capacity per unit mass. the amount of energy transfer necessary to raise the temperature of 1 g of water from 14.5°C to 15.5°C. the amount of energy needed to raise the temperature of the sample by 1°C.

Students design an experiment with a curved, insulated rod of an unknown thermally conducting material, as shown in the figure. The rod is 1m long and 2 cm in diameter. One end of the rod is touching the surface of water kept at 350 K by a hot plate, and the other end is just touching the surface of a well-insulated block of ice. The students are required to create a procedure to determine the thermal conductivity of the rod. They first determine that they can measure the amount of ice that has melted after a given time to calculate the heat transfer over time to the block of ice. Which of the following must the students also measure to calculate the thermal conductivity of the rod?

The temperature in Paris, France, one summer day is 27.7°C. Meanwhile, the temperature in Paris, TN, is 87.1°F. Answer the three parts below, using three sig figs. Part A - What is the temperature in France, TFr, in degrees Farenheit? Part B - What is the absolute difference, ΔT between the temperature in the two cities (in Kelvin)?

1) 150 g of a liquid at 45ºC is filled in an insulated metal container at 35°C whose mass is 110 g. The system eventually reaches an equilibrium. Find: (a) the final equilibrium temperature, and (b) estimate total change in entropy of the system (i.e. metal container plus liquid) . Specific heat of liquid is 4186 J/kg . Cº and specific heat of metal is 900 J/kg. C°. [5 pts]

An object with initial temperature 150°C is placed outside, where the temperature is 35°C. Its temperatures at 12:15 and 12:20 are 120°C and 90°C, respectively. (a) At what time was the object placed outside? (b) When will its temperature be 40°C?

A small hole of radius 1 cm is made in a blackened spherical shell of radius 2m. Inside the shell we have another concentric blackened sphere of radius 1m. The inner sphere is perfectly conducting Sun light of intensity 1600 W/m² falls through the hole on the inner shell in a direction perpendicular to the surface. The shell is also perfectly conducting and is located in vacuum. No radiations are falling from sun on the outer surface of the shell. Choose the correct statement(s): A. The radiation spectrum coming out from the hole will be same as that of a black body at the temperature of the inner sphere. B. The steady state temperature of the sphere is close to 30 K C. The steady state temperature of the shell is close to 20 K D. The steady state temperature of the shell is close to 10 K

As the molecules of a substance gain heat energy, which of the following occurs? A. they increase in size due to the added energy B. they have more kinetic energy because they are vibrating faster C. they decrease in size due to the added energy D. they have more kinetic energy because collisions are occurring less frequently

Compare the rate of radiation by a blackbody at 727 °C with that at 427 °C. Also compare its rate of loss of heat at the two temperatures, if the temperature of the surroundings is 27 °C.

Lake Erie contains roughly 4.00 x 1011 m³ of water. (a) How much energy is required to raise the temperature of that volume of water from 15.8°C to 20.2°C? (Assume the density of this water to be equal to that of water at 20°C and 1 atm.) (b) How many years would it take to supply this amount of energy by using the 1,400-MW exhaust energy of an electric power plant?

An unknown substance at 94.5°C with a mass of 55 g is added to 134 g of water at 22°C. The final equilibrium temperature is 26.6°C. What is the specific heat of the unknown substance?

Conduction, Convection, or Radiation? Which type (or types) of heat transfer is demonstrated by the following example? the metal slide at the playground becomes too hot to slide down (hint: what is MAKING the slide hot?) radiation conduction none convection

Conduction, Convection, or Radiation? Which type of heat transfer is demonstrated by the following example? macaroni rises and falls as it cooks in a pot of water radiation convection conduction none

3. A chemist mixes 500 g of lead at 500°C with 1,200 g of water at 20°C. She then mixes 500 g of copper at 500°C with 1,200 g of water at 20°C. The specific heat capacity of lead is 0.1276 J/g°C and the specific heat capacity of copper is 0.3845 J/g°C. What will be true about the final temperatures of the two systems? A. The final temperature of the lead-water system will be equal to the final temperature of the copper-water system. B. The final temperature of the lead-water system will be higher than the final temperature of the copper-water system. OC. The final temperature of the lead-water system will be lower than the final temperature of the copper-water system. D. Cannot be determined from the given information.

In class we discussed how a heat pump works (either with just a gas or with a 'refrigerant'). Describe in a paragraph (with a diagram if you'd like) how a refrigerator or air conditioner would work on a hot summer day.

Suppose a woman does 500 J of work and 9500 J of heat transfer occurs into the environment in the process. (a) What is the decrease in her internal energy, assuming no change in temperature or consumption of food? (That is, there is no other energy transfer.) (b) What is her efficiency? (Recall that efficiency is work output/energy input)

A 0.250-kg block of a pure material is heated from 20°C to 65°C by the addition of 4.35 kJ of energy. Calculate its specific heat and identify the substance of which it is most likely composed. (Use the tables from the slides or chapter 14.2.)

An ice chest at a beach party contains 48 cans of soda at 9 °C. Each can of soda has a mass of 0.35 kg and a specific heat capacity of 3800 J/(kg C°). Someone adds a 14.25-kg watermelon at 27 °C to the chest. The specific heat capacity of watermelon is approximately the same as that of water. Ignore the specific heat capacity of the chest and determine the final temperature T of the soda and watermelon in degrees Celsius.