Question

A flask capacity 1 liter is heated form 250c to 350c. What volume of air will escape from the flask?

Answer 1

A flask with capacity of 1 liter is heated from $250^{\circ}\mathrm{C}$ to $350^{\circ}\mathrm{C}$. What volume of air will escape from the flask?

Solution: In this process the isobaric heating occurs, because pressure of the air in the flask is constant and equals to the atmospheric pressure. According to the combined gas law, $\frac{P \cdot V}{T} = \text{const}$, and when

$$P = \text{const}, \text{ then } \frac{V}{T} = \text{const}; \frac{V_1}{T_1} = \frac{V_2}{T_2}, V_2 = \frac{V_1 \cdot T_2}{T_1}, \Delta V = V_2 - V_1 = \frac{V_1 \cdot T_2}{T_1} - V_1 = V_1 \cdot \left(\frac{T_2}{T_1} - 1\right);$$ $$T_1 = 250 + 273 = 523 \, \text{K}; \quad T_2 = 350 + 273 = 623 \, \text{K};$$ $$\Delta V = 1 \cdot 10^{-3} \cdot \left(\frac{623}{523} - 1\right) = 1.91 \cdot 10^{-4} \, \text{m}^3 = 0.191 \, \text{liters}.$$

Answer: 0.191 liters.