Lv 1183 points

# Bilal

• ### A 31.8-g ice cube is initially at 0.0°C.?

A 31.8-g ice cube is initially at 0.0°C.

(a) Find the change in entropy of the cube after it melts completely at 0.0°C. Hint: The latent heat of fusion for water is 3.33 10^5 J/kg.

(b) What is the change in entropy of the environment in this process?

• ### A 68.0-kg log falls from a height of 23.0 m into a lake. ?

A 68.0-kg log falls from a height of 23.0 m into a lake. If the log, the lake, and the air are all at 304 K, find the change in entropy of the Universe during this process.

Has to be in J/K

Physics2 months ago
• ### Find the numeric value of the work done on the gas in the following figures. (Enter your answers in J.)?

Find the numeric value of the work done on the gas in the following figures. (Enter your answers in J.)

• ### For the two PV diagrams below, find the net work done on the gas during the process indicated by the path. (Enter your answers in J.)?

For the two PV diagrams below, find the net work done on the gas during the process indicated by the path. (Enter your answers in J.)

• ### What is the change in entropy of 1.00 kg of liquid water at 100°C as it changes to steam at 100°C?  Has to be in J/K ?

What is the change in entropy of 1.00 kg of liquid water at 100°C as it changes to steam at 100°C?

• ### A freezer sits in a large room. A container of liquid water, with a volume of 4.7 L and at a temperature of 0°C?

A freezer sits in a large room. A container of liquid water, with a volume of 4.7 L and at a temperature of 0°C, is placed in the freezer, where it is completely converted into ice. Throughout the freezing process, the interior of the freezer is maintained at a temperature of 0°C.

(a) Find the change in entropy (in kJ/K) of the water during the freezing process.(b) Find the change in entropy (in kJ/K) of the interior of the freezer (not including the water) during the freezing process.(c) The freezer's coefficient of performance (cooling mode) is 4.00. How much heat (in J) does the freezer expel to the room in which the freezer sits during the freezing process? Give the absolute value.(d) If the room that houses the freezer stays at a constant temperature of 20.0°C, what is the total entropy change (of the water, freezer interior, and the room combined, in kJ/K) during the freezing process?

• ### In each cycle of its operation, a heat engine expels 4,000 J of energy and performs 2,000 J of mechanical work?

In each cycle of its operation, a heat engine expels 4,000 J of energy and performs 2,000 J of mechanical work.

(a) How much thermal energy must be added to the engine in each cycle?

(b) Find the thermal efficiency of the engine.

• ### A balloon holding 4.50 moles of nitrogen (N2) gas absorbs 895 J of thermal energy while doing 127 J of work expanding to a larger volume.?

A balloon holding 4.50 moles of nitrogen (N2) gas absorbs 895 J of thermal energy while doing 127 J of work expanding to a larger volume.

(a) Find the change in the balloon's internal energy (in J).

(b) Calculate the change in temperature of the gas (in K).

• ### A sample of gas in a cylinder is compressed by a piston at a constant pressure of 0.800 atm. ?

A sample of gas in a cylinder is compressed by a piston at a constant pressure of 0.800 atm. The volume of the cylinder decreases from 7.50 L to 3.00 L, while at the same time 340 J of energy leaves the gas by heat.

(a) What is the work done on the gas (in J)?(b) What is the change in its internal energy (in J)?

• ### A cylinder with a moveable piston on top, free to move up and down, contains one mole of an ideal gas initially at a temperature of Ti=4.0°C?

A cylinder with a moveable piston on top, free to move up and down, contains one mole of an ideal gas initially at a temperature of Ti = 4.0°C. The cylinder is heated at a constant pressure of 1.00 atm, and it expands to three times its original volume.

(a) Calculate the new temperature Tf of the gas (in K).(b) Calculate the work done (in kJ) on the gas during the expansion.

• ### The rate of heat conduction out of a window on a winter day is rapid enough to chill the air next to it.?

To see just how rapidly windows conduct heat, calculate the rate of conduction in watts through a 3.32 m2 window that is 0.655 cm thick if the temperatures of the inner and outer surfaces are 5.00°C and −10.0°C, respectively. This rapid rate will not be maintained — the inner surface will cool, and frost may even form. The thermal conductivity of glass is 0.84 J/(s · m · °C).

• ### A 2.43-g lead bullet traveling at 478 m/s strikes a target, converting its kinetic energy into thermal energy. ?

A 2.43-g lead bullet traveling at 478 m/s strikes a target, converting its kinetic energy into thermal energy. Its initial temperature is 40.0°C. The specific heat is 128 J/(kg · °C), latent heat of fusion is 24.5 kJ/kg, and the melting point of lead is 327°C.

(a) Find the available kinetic energy of the bullet.

(b) Find the heat required to melt the bullet.

• ### To help prevent frost damage, 4.07 kg of 0°C water is sprayed onto a fruit tree. The latent heat of fusion of water is 79.8 kcal/kg.?

To help prevent frost damage, 4.07 kg of 0°C water is sprayed onto a fruit tree. The latent heat of fusion of water is 79.8 kcal/kg.

(a) How much heat will be released by the water as it freezes?

(b) How much would the temperature of the 180-kg tree decrease if it lost this amount of heat, given its specific heat is 0.800 kcal/(kg · °C), and no phase change occurs?

• ### A 2.43-g lead bullet traveling at 478 m/s strikes a target, converting its kinetic energy into thermal energy.?

Its initial temperature is 40.0°C. The specific heat is 128 J/(kg · °C), latent heat of fusion is 24.5 kJ/kg, and the melting point of lead is 327°C.

(a) Find the available kinetic energy of the bullet.

(b) Find the heat required to melt the bullet.

• ### An ice bag containing 0°C ice is much more effective in absorbing heat than one containing the same amount of 0°C water. ?

The specific heat capacity of water is 1.00 kcal/(kg · °C), and its latent heat of fusion is 79.8 kcal/kg.

(a) How much heat in kcal is required to raise the temperature of 0.510 kg of water from 0°C to 26.0°C?

(b) How much heat is required to first melt 0.510 kg of 0°C ice and then raise its temperature to 26.0°C?

• ### In a physics lab students are conducting an experiment to learn about the heat capacity of different materials.?

The first group is instructed to add 1.5-g copper pellets at a temperature of 92°C to 185 g of water at 16°C. A second group is given the same number of 1.5-g pellets as the first group, but these are now aluminum pellets. Assume that no heat is lost to or gained from the surroundings for either group.

(a) If the final equilibrium temperature of the copper pellets and water is 25°C, how many whole pellets did the first group use in the experiment? The specific heat of copper is 0.0924 kcal/(kg · °C). (b) Will the final equilibrium temperature for the second group be higher, lower, or the same as for the first group? The specific heat of aluminum is 0.215 kcal/(kg · °C).       (A) higher       (B) lower           (C) the same(c) What is the equilibrium temperature of the aluminum and water mixture for the second group?

• ### Samantha wishes to maintain her weight and goes to the gym to work off the calories she consumed at breakfast that morning. ?

She lifts a 26.0-kg barbell from shoulder level to above her head, through a vertical height of 0.550 m. How many times must she lift the barbell to make up for the 3.40 102 Calories of energy she consumed at breakfast? Note that Calories refers to food calories. (Include lowering the barbell as well.)

Diet & Fitness3 months ago
• ### A piece of iron block moves across a rough horizontal surface before coming to rest.?

The mass of the block is 1.8 kg, and its initial speed is 3.5 m/s. How much does the block's temperature increase, if it absorbs 78% of its initial kinetic energy as internal energy? The specific heat of iron is 452 J/(kg · °C).