Opgaver om kredsprocesser

Fysik opgaver af Jonas, Mike og Martin.

Opgave 1

LaTex: \begin{eqnarray} p_a &=& p_d = 2 MPa\\ p_b &=& p_c = 16 MPa\\ T_a &=& 300 K\\ T_c &=& 870 K\\ \gamma &=& 1,4\\ T_b &=& T_a \cdot \left( \sqrt[\gamma]{\frac{p_b}{p_a}} \right)^{\gamma-1} = 543,43 K\\ T_d &=& T_c \cdot \left( \sqrt[\gamma]{\frac{p_d}{p_c}} \right)^{\gamma-1} = 480,28 K\\ \eta &=& 1 - \frac{T_d-T_a}{T_c-T_b} = 0,448\\ \end{eqnarray}

(Se eksempel 1 nr. 2 i arkene om termodynamik.)

Opgave 2

LaTex: \begin{eqnarray} V_1 &=& 1,5 L\\ T_1 &=& 20 C = 293,15 K\\ p_1 &=& 145 kPa\\ M &=& 28,0 \frac{g}{mol}\\ n &=& \frac{p_1 \cdot V_1}{R\cdot T_1} = 89,23 mmol\\ m &=& n \cdot M = 2,5 g\\ V_2 &=& 1,35 L\\ p_2 &=& 170 kPa\\ T_2 &=& \frac{p_2\cdot v_2\cdot t_1}{p_1\cdot v_1} = 309,32 K\\ \end{eqnarray}

Opgave 3

LaTex: \begin{eqnarray} n &=& 2 mol\\ V &=& 10 L\\ p &=& 1 atm\\ T &=& 400 K\\ V_1 &=& \frac{n\cdot R\cdot T}{p} = 65,64 L\\ A_{tilf} &=& 25 kJ = -n\cdot R\cdot T ln\left(\frac{V_2}{V_1}\right)\\ V_2 &=& V_1\cdot e^{\frac{A_{tilf}}{-n\cdot R\cdot T}} = 1,53 L\\ T_0 &=& \frac{p\cdot V}{n\cdot R} = 60,93 K\\ Q &=& 29,4 \frac{J}{mol\cdot K} n\cdot (T -T_0) = 19,94 kJ\\ \end{eqnarray}

B)
Man formindsker volument, mens man køler på den.
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