Suppose you start with a liquid mixture of 60% nitrogen and 40% oxygen.
Describe what happens as the temperature of this mixture increases. Be sure to
give the temperatures and compositions at which boiling begins and ends.
To answer this question, we need to understand the concept of boiling and the properties of nitrogen and oxygen.
Boiling is the process in which a liquid changes to a gas by the formation of bubbles throughout the liquid. The boiling point of a substance is the temperature at which its vapor pressure equals the pressure of the surrounding environment. At this point, bubbles of gas can form within the liquid.
Nitrogen and oxygen are both gases at standard temperature and pressure (STP). Nitrogen has a boiling point of -196 degrees Celsius (-321 degrees Fahrenheit), while oxygen has a boiling point of -183 degrees Celsius (-297 degrees Fahrenheit).
Initially, we have a liquid mixture of 60% nitrogen and 40% oxygen. As the temperature rises, the kinetic energy of the molecules increases, leading to an increase in vapor pressure. When the temperature reaches the boiling point of the component with the lower boiling point, bubbles of that component start to form within the liquid.
In this case, nitrogen has the lower boiling point, so boiling will begin when the temperature reaches -196 degrees Celsius. At this temperature, some of the nitrogen molecules will start to vaporize, and the mixture will transition from a liquid phase to a gas-liquid phase.
As the temperature continues to rise, more nitrogen will vaporize, and the composition of the remaining liquid mixture will change. The concentration of oxygen in the liquid phase will increase, while the concentration of nitrogen will decrease.
Boiling ends when the last bit of liquid has converted into a gas. This occurs when the temperature reaches -183 degrees Celsius, the boiling point of oxygen. At this temperature, all the remaining liquid will have vaporized, and the mixture will be entirely in the gas phase, composed of 60% nitrogen and 40% oxygen.
In summary, as the temperature increases, the liquid mixture of 60% nitrogen and 40% oxygen will start boiling at -196 degrees Celsius, and it will completely vaporize into a gas mixture of 60% nitrogen and 40% oxygen when the temperature reaches -183 degrees Celsius.