Thermodynamics sections 2.6-2.8

A system containing an electric device is well-insulated. If the energy of the system increases 16 kJ during a process, what is the electric work performed on the system?

16kJ,

Reason:

The change in the total energy during an adiabatic process must be equal to the net work done.

During a process, if the state of the system does not change, the system energy will:

Stay the same

Select all that apply

Energy transfer is involved in each of the following systems. Select the ones that involves mainly work interaction.

Multiple select question.

A gas turbine

Boiling water on a gas stove

A rising piston

Water heated in a tub

A rotating shaft

A gas turbine

A rising piston

A rotating shaft

8 kW of shaft work is done on a system while 3 kW of heat is lost from the system. What is the rate of energy change of the system?

5 kW

Reason: Win-Wout => 8-3=5

For a cooking appliance, the overall energy supplied to the appliance is 5 kWh and only 4 kWh is transferred to the food. What is the appliance's efficiency?

0.8 Reason:

Efficiency is defined by energy utilized divided by energy supplied to the appliance.

4/5=0.8

A potato is baked in an oven. Considering that any moisture loss from the potato is disregarded and the oven is well insulated, if 2 kJ of heat is transferred to the potato, what is the energy change of the potato?

2 kJ

Reason:

The first law of thermodynamics must be preserved as energy can neither be created nor destroyed. If the potato receives a heat transfer of 2 kJ, then its energy must increase by 2 kJ as well.

Select all that apply

Identify the true statements about the effect of energy conversion on environment.

Multiple select question.

The conversion of energy has lead to the accumulation of fossil fuels.

The conversion of energy has a positive effect on the soil we farm and the water we drink to the air we breathe.

The conversion of energy has lead to air pollution that has been the cause of numerous health problems, including asthma and cancer.

The combustion of fossil fuels is responsible for smog, acid rain, global warming, and climate change.

The conversion of energy has lead to air pollution that has been the cause of numerous health problems, including asthma and cancer.

The combustion of fossil fuels is responsible for smog, acid rain, global warming, and climate change.

For a simple compressible system, the change in the total energy of a system during a process is affected by:

changes in potential, kinetic, and internal energies.

When a mass enters a system, the energy in the system:

Increases

Mass carries energy with it

Select all that apply

Which of the following statements are true of the energy transfer?

Multiple select question.

The work transfer W is zero for adiabatic systems.

The work transfer W is zero for systems that involve no work interactions.

The energy transport with mass is zero for adiabatic systems.

The heat transfer Q is zero for adiabatic systems.

The work transfer W is zero for systems that involve no work interactions.

The heat transfer Q is zero for adiabatic systems.

Efficiency can be expressed in terms of the desired______divided by the required________

output, input

In 1997, the world's industrialized countries adopted the Kyoto protocol and committed to reduce by 2008 to 2012 their CO2 and other greenhouse gas emissions by 5% below the 1990 levels.

True (why is this a question who cares didnt work anyway)