PART B AND D NEED HELP PhET Simulation - Energy Forms and Changes NOTE: These ac

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PART B AND D NEED HELP

PhET Simulation - Energy Forms and Changes

NOTE: These activities use Java, and are therefore not screen-reader accessible and may not work on a mobile device. If the browser you’re using no longer supports Java, try a different browser and download the Java plugin for this content.

Energy can exist in a variety of forms. Energy is never lost, but rather it is converted between forms. When examining a system, the internal energy of that system can change such that it loses/gains energy to/from its surroundings, and the form of energy does not matter. The change in the internal energy of a system is:

?E=Efinal?Einitial

which can also be simply represented by:

E = q + w

where q signifies the heat absorbed (or released) by the system, and w signifies the work done on a system. The values for q and w can be negative if the system loses heat or performs work, respectively. The processes of energy transfer can be described as endothermic (endo-, energy going into system) or exothermic (exo-, energy leaving system).

Click on the image to explore this simulation, which shows the how energy is transferred between objects in either the same form or through conversions. When you click the simulation link, you may be asked whether to run, open, or save the file. Choose to run or open it.

When the simulation is opened, you will see various objects that can be placed on a heating/cooling surface. Checking the “Energy Symbols” box in the upper right allows you to view the internal energy of the objects and the transfer of thermal energy. Clicking the Energy Systems tab of the simulation allows you to view energy conversions by connecting different energy producing and energy converting sources. There are twelve different working configurations for these sources.

Part A

In the PhET simulation window, click on the Intro tab and check the “Energy Symbols” box in the upper right. Perform the described tasks and fill in the blanks with the appropriate terms.

Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer.

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1. Drag the beaker of water onto the support. The internal energy of water will be analyzed, which makes water the system being studied.

2. When the slider is dragged down to cool the water, the water loses thermal energy to the ice, and the ice is considered part of the surroundings.

3. This transfer of heat is an exothermic process, and the sign on the value for qsys would be negative.

4. When the water is heated, the water undergoes an endothermic process, and it gains thermal energy from the fire.

5. In this situation, the sign on the value for qsys would be positive.

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The internal energy can have a different sign than heat depending on the magnitude of work performed on or by the system. The described situations have assumed no work was being performed, which signify that ?E=q for all processes.

Conversion of Energy

Even if energy seems to disappear, it is never lost, but rather it is converted between forms. This is the principle described in the first law of thermodynamics. Potential energy can be stored in a system before it is converted to kinetic energy, and many transformations of energy can occur to drive a process (perform work).

Part B

In the PhET simulation window, click the Energy Systems tab, check the “Energy Symbols” box in the upper right, and use the simulation to recreate the illustrated energy conversion processes. Observe the forms of energy as they are converted and correctly identify the energy conversions for each.

Drag the appropriate systems to their respective targets.

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Heat capacity

Heat capacity refers to how much energy a material can absorb with respect to changes in average kinetic energy, and its specific heat capacity quantifies the exact amount of energy it takes to raise 1 g of the material's temperature by 1 ?C (depending on the units, which can sometimes refer the moles of material). Heat capacity refers to the temperature changes in the same state of matter, whereas the per unit energies required to melt and boil a substance are called the enthalpies of fusion and vaporization, respectively.

The relationship between heat and temperature change is described by the following equation:

q = mcs?T

where q is the heat absorbed or lost, m is the mass, cs is the specific heat, and ?T is the change in temperature.

Part C

Suppose 1 kg each of water (4.19 J/g??C), brick (0.90 J/g??C), iron (0.46 J/g??C), and plastic (1.01 J/g??C) were held at the same initial temperature and heated for an equivalent amount of time. Indicate the relative final temperatures by ordering from lowest to highest resulting temperature (if using the Intro tab of the PhET to help visualize the temperature changes, assume the water iron, and plastic are 1 kg in mass, and the brick has a mass of 0.5 kg). Assume no heat is lost to the surroundings.

Rank from lowest resulting temperature to highest resulting temperature. To rank items as equivalent, overlap them.

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Highest resulting temperature

Lowest resulting temperature

Water

Plastic

Brick

Iron

The correct ranking cannot be determined.

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In reality, different formulations of plastic, brick, or even iron would lead to different heat capacities. Typically, brick and concrete have higher specific heats than most metals, which make them more resistant to temperature changes, and the heat capacities of plastics can vary more widely.

Part D

A 1.9 kg block of iron at 30 ?C is rapidly heated by a torch such that 13 kJ is transferred to it. What temperature would the block of iron reach assuming the complete transfer of heat and no loss to the surroundings? If the same amount of heat was quickly transferred to a 890 g pellet of copper at 23 ?C, what temperature would it reach before losing heat to the surroundings?

qcs, Fe(s)cs, Cu(s)===mcs?T0.450 J/g??C0.385 J/g??C

Express the final temperatures of the iron and copper in ?C to two significant figures separated by a comma.

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1. Drag the beaker of water onto the support. The internal energy of water will be analyzed, which makes water the system being studied.

2. When the slider is dragged down to cool the water, the water loses thermal energy to the ice, and the ice is considered part of the surroundings.

3. This transfer of heat is an exothermic process, and the sign on the value for qsys would be negative.

4. When the water is heated, the water undergoes an endothermic process, and it gains thermal energy from the fire.

5. In this situation, the sign on the value for qsys would be positive.

Intro Energy Syste Energy Symbols Water Iron Brick °Normal Fast Forward Reset Al

Explanation / Answer

Part B : To correctly identify the energy conversions, simulation has to be done which I am unable to do so

If you can provide the online link to simulation, then I can help

Part D

Final temperatures of Fe, Cu = 45 , 61 oC

Qtransfer = m.C.(delta T)

For Fe, Qtransfer = 13 kJ = 13000 J

m = 1.9 kg = 1900 g

C = 0.450 J/g-oC

delta T = T - 30oC , where T = final temperature

13000J = (1900g) x (0.450 J/g-oC) x (T - 30oC)

Solving, we get TFe = 45 oC

Similarly for Cu, Qtransfer = 13 kJ = 13000 J, m = 890 g , C = 0.385 J/g-oC , delta T = T - 23oC

13000J = (890g) x (0.385 J/g-oC) x (T - 23oC)

Solving, we get TCu = 61 oC

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