https://padlet.com/tec430/w891kldtdzgy (1) Explain how heat and work transfer from a system (2) What is the formula for work done by a gas? (3) How is pressure, volumne and diplacement related when explaining how work can be done by a gas? (4) A gas in a cylinder has an area of 2 m squared and a piston that moves 0.25m. If the gas exerts a constant pressure of 7.5 x10^5 Pa, what i sthe work done by the gas? (5) Uing the equation for the firt Law of Thermodynamics, If the total work done by a gas i 12J and the internal energy done by the ga increae by 115J, what i the total amount of energy tranferred as heat (Q)? (6) Using the Second Law of Thermodynamics, if the net work done by a ga engine is 50J and the engine gives up 30J of heat, what is the engines efficiency? en-us 2017-02-06 16:43:17 UTC 2017-02-06 23:49:44 UTC hello@padlet.com https://padlet.com/tec430/w891kldtdzgy/wish/151997566 1. Heat is transferred by conduction in solids, convection of fluids (liquids or gases), and radiation through anything that will allow radiation to pass. Work is done on an object which transfers energy.
2. Work=Pressure x Volume
3. When a gas explodes and causes a container to increase, volume increases, and there is more work done.
4. W=PV
W=(7.5x10^5Pa)(2m^2 x 0.25m)= 3.75x10^5 Pa m^3
5. ΔU(Change in Internal Energy)=q(heat added to system)+w(Work done by system)
115J=Q+12J
Q=103J
6. Efficiency of engine=Work output/ Work input= 50 J/ 30 J= 1.67 J


]]> 2017-02-06 23:02:06 UTC https://padlet.com/tec430/w891kldtdzgy/wish/151997566 https://padlet.com/tec430/w891kldtdzgy/wish/151997659 1. According to the first law of thermodynamics the change in internal energy of a system is equal to the heat added to a system minus the work done by the system. 
2. The formula for work done by a gas is w=-Pexternal times change in V.
3. When gas moleculues are heated, they move faster (increase in kinetic energy) and thus increase the pressure and increase the volume (P1V1=P2V2). Work=force x displacement. 
4. 2m^2 x 0.25 m = 0.5 m^3
7.5x10^5 pa = 7.4019245 atm
0.5 m^3 x 7.4019245 atm=  3.70 N
5. First law of thermodynamics change in iiternal energy of a system change V equals net heat transfer. 12 J=w
115J=12+Q
Q=103J
6. 50 J - 30 J = 20 J for work
20J/50 J = 40%]]> 2017-02-06 23:02:44 UTC https://padlet.com/tec430/w891kldtdzgy/wish/151997659 https://padlet.com/tec430/w891kldtdzgy/wish/151998146 1) Heat ]]> 2017-02-06 23:08:00 UTC https://padlet.com/tec430/w891kldtdzgy/wish/151998146 https://padlet.com/tec430/w891kldtdzgy/wish/151998178 1) Heat occurs when an object with high thermal energy comes into contact with low thermal energy. Work is done on an object which transfer energy.  
2) Work equals pressure time change of volume 
3) They are all directly related, when one increases the others increase too.
4)Work= (7.5x10^5pa)(2x.25)= 375000 Pa 
5)115J-12J =103J
6)  50J -30J =20J for work.  WO/WI which is 20J/50J = 40% efficiency. ]]> 2017-02-06 23:08:24 UTC https://padlet.com/tec430/w891kldtdzgy/wish/151998178 https://padlet.com/tec430/w891kldtdzgy/wish/151998259 1. Heat transfers by thermal interaction (conduction, convection, and/or radiation). Work transfers energy in any other way than heat (mechanical, electrical, chemical, etc). 
2. W = P * ∆V
3. When displacement decreases, volume decreases, and pressure decreases, completing work. 
4. W = (7.5 * 10^5 Pa)(2*.25) = 375000 Pa
5. 115 J - 12 J = 103 J
6. 50 J / 30 J = 1.67 ]]> 2017-02-06 23:09:13 UTC https://padlet.com/tec430/w891kldtdzgy/wish/151998259 https://padlet.com/tec430/w891kldtdzgy/wish/151998626 1. Heat is transferred through conductions (solids), convection (liquids/gasses), and radiation. Work is dope on an object if it transfers energy. 
2. Work=pressure*change in volume
3. Volume, displacement, and pressure are all all directly related, so when one increases or decreases, the others do the same to complete work. 
4. W= (7.5x10^5Pa)(2*.25)= 375000 Pa or 3.75x10^5 Pa
5. 115 J - 12J = 103J
6. 50J-30J= 20J of work
20J/50J= 40% efficiency

]]> 2017-02-06 23:12:56 UTC https://padlet.com/tec430/w891kldtdzgy/wish/151998626 https://padlet.com/tec430/w891kldtdzgy/wish/151998858 1)Heat is transferred by cnduction by liquids then when the explosion takes place work is then done on an object and  creates energy. 
2) W=P*V
3)When the explosion takes place the container expand and to press out more work is done.
4)W=(7.5*10^5 Pa)*(2*.25)=375000Pa
5)115J- 12J=103J
6)]]> 2017-02-06 23:15:52 UTC https://padlet.com/tec430/w891kldtdzgy/wish/151998858