if oxygen is removed from a sample of airas iron rusts , what happens to the total pressure of the air ?

it decreases

If oxygen is removed from a sample of air as iron rusts, the total pressure of the air would decrease. This is because oxygen is one of the components of air, and when it reacts with iron to form rust, it is effectively being removed from the air sample. As a result, the overall number of gas molecules in the sample would decrease, leading to a reduction in the total pressure of the air.

When oxygen is removed from a sample of air, the total pressure of the air will decrease. This is because oxygen is one of the components of air, and the pressure exerted by a gas is directly proportional to the number of gas molecules that are present. So, when oxygen is removed, there are fewer gas molecules in the sample, resulting in a decrease in the total pressure.

To understand why this happens, you can use the ideal gas law, which relates the pressure, volume, temperature, and number of moles of a gas. The ideal gas law is expressed as:

PV = nRT

Where:
- P is the pressure of the gas
- V is the volume occupied by the gas
- n is the number of moles of the gas
- R is the ideal gas constant
- T is the temperature in Kelvin

In this case, the volume and temperature of the sample of air are assumed to remain constant. If oxygen is removed from the sample, the number of moles of gas (n) decreases. Therefore, according to the ideal gas law, the pressure (P) will also decrease.

In summary, when oxygen is removed from the air, the total pressure of the air decreases due to a reduction in the number of gas molecules present in the sample.