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A fuel-air mixture is placed in a cylinder fitted with a piston. The original volume is 0.310-L. When the mixture is ignited, gases are produced and 935 J of energy is released. To what volume will the gases expand against a constant pressure of 635 mmHg, if all the energy released is converted to work to push the piston? □ 12.8 L 114L 9.02L 10.2L

Respuesta :

Giangiglia

Answer:

[tex]V_2=11.35L[/tex]

Explanation:

Knowing that the system is at constant pressure, the energy balance is:

[tex]\Delta H=Q-W[/tex]

If all the energy (enthalpy of combustion) is transformed into work:

[tex]\Delta H=-W[/tex]

Work:

[tex]W=-\int_{V1}^{V2}P*dV[/tex]

[tex]W=-P*(V_2-V_1)[/tex]

[tex]\Delta H=P*(V_2-V_1)[/tex]

Calculating:

[tex]935J=84659 Pa*(V_2-3.1*10^{-4}m^3)[/tex]

[tex]V_2=0.0113 m^3=11.35L[/tex]

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