Some is released if the temperature is increased. Some O2 is always entering and leaving solution at the same time. You end up with an equilibrium between the two processes.

The given statement describes the process of gas solubility in a liquid and how it reaches equilibrium. Let's break it down and explain it further:

1. "Some is released if the temperature is increased":
When a gas is dissolved in a liquid, the solubility of that gas generally decreases as the temperature of the liquid increases. This means that if you heat up the solution, some of the gas molecules will be released from the liquid and escape into the atmosphere.

2. "Some O2 is always entering and leaving solution at the same time":
In a closed system, like a container of liquid, gas solubility is a dynamic process. Even when the solution is at equilibrium, where the rate of dissolution of gas molecules in the liquid is equal to the rate of escape from the liquid, some gas molecules are continuously entering and leaving the solution. This constant flow of gas in and out maintains the equilibrium state.

3. "You end up with an equilibrium between the two processes":
Equilibrium is reached when the rate of gas molecules dissolving in the liquid is equal to the rate of gas molecules escaping from the liquid. At this point, the concentration of the gas in the liquid remains constant over time. It's important to note that equilibrium doesn't mean that there is an equal amount of gas in the liquid and in the air above the liquid. Instead, it refers to the balance achieved between the two opposing processes.

In summary, when a gas is dissolved in a liquid, the solubility of the gas decreases as the temperature increases, allowing some of the gas molecules to be released. However, even at equilibrium, there is a continuous exchange of gas molecules between the liquid and the surrounding atmosphere, maintaining a dynamic balance between the dissolution and escape of gas from the liquid.