1) Does a fire burning in a fireplace represent an equilibrium situation? Why or why not?
2) Does the following represent a equilibrium situation? Liquid mercury and mercury vapour are found in a thermometer.
1. No, because gases are not contained; i.e., they are exiting through the chimney.
2. Yes, the Hg vapor and Hg liquid are confined.
1) To determine whether a fire burning in a fireplace represents an equilibrium situation, we need to understand what an equilibrium situation means. In chemistry, an equilibrium is a state where the rate of a forward reaction equals the rate of the reverse reaction, resulting in a stable system.
A fire is not an equilibrium situation because it involves a highly exothermic (heat-releasing) combustion reaction. In a fireplace, the burning of wood or fuel releases heat, light, and various gases like carbon dioxide and water vapor. These reactions are not reversible in the same way that chemical equilibrium is achieved. Once the wood is consumed and the fuel is burned, the reaction cannot be easily reversed to return to the initial state and maintain a constant temperature.
In summary, a fire burning in a fireplace does not represent an equilibrium situation primarily because it involves irreversible combustion reactions instead of reversible reactions.
2) In the case of a thermometer containing liquid mercury and mercury vapor, it represents an equilibrium situation. A thermometer utilizes the thermal expansion of mercury to measure temperature. Mercury is a unique substance with a relatively high vapor pressure, which means it can exist in both liquid and vapor form at room temperature.
By containing both liquid mercury and mercury vapor, the thermometer achieves an equilibrium situation. At equilibrium, the rate of evaporation (vaporization) of the liquid mercury equals the rate of condensation of the mercury vapor. The presence of these two phases indicates that the system has reached a stable state where the temperature is accurately measured.
In conclusion, the presence of liquid mercury and mercury vapor in a thermometer represents an equilibrium situation because the rates of evaporation and condensation are in balance.