# Relationship between pressure and volume of gas

### Relationships among Pressure, Temperature, Volume, and Amount - Chemistry LibreTexts

to Boyle's Law, an inverse relationship exists between pressure and volume. P2 and V2 are the values of the pressure and volume of the gas after change. Nov 14, The pressure (P) of gas is inversely proportional to the volume (V) of gas. This means that as we hold temperature (T) constant (same), as the. Boyle's law relates the pressure and volume of an ideal gas. Robert Boyle studied the relationship between the pressure p and the volume V of a confined gas.

## What is the relationship between pressure and volume?

Boyle used a J-shaped tube partially filled with mercury, as shown in Figure 6. In these experiments, a small amount of a gas or air is trapped above the mercury column, and its volume is measured at atmospheric pressure and constant temperature.

• Pressure and volume relationship of a gas
• Boyle's law

More mercury is then poured into the open arm to increase the pressure on the gas sample. The pressure on the gas is atmospheric pressure plus the difference in the heights of the mercury columns, and the resulting volume is measured.

Animation : Relationship of Pressure with Volume and Temperature

This process is repeated until either there is no more room in the open arm or the volume of the gas is too small to be measured accurately.

This relationship between the two quantities is described as follows: Dividing both sides of Equation 6. The numerical value of the constant depends on the amount of gas used in the experiment and on the temperature at which the experiments are carried out. At constant temperature, the volume of a fixed amount of a gas is inversely proportional to its pressure. Boyle used non-SI units to measure the volume in. Hg rather than mmHg. Because PV is a constant, decreasing the pressure by a factor of two results in a twofold increase in volume and vice versa.

The Relationship between Temperature and Volume: Charles's Law Hot air rises, which is why hot-air balloons ascend through the atmosphere and why warm air collects near the ceiling and cooler air collects at ground level.

## 6.3: Relationships among Pressure, Temperature, Volume, and Amount

Because of this behavior, heating registers are placed on or near the floor, and vents for air-conditioning are placed on or near the ceiling. The fundamental reason for this behavior is that gases expand when they are heated.

Because the same amount of substance now occupies a greater volume, hot air is less dense than cold air. The substance with the lower density—in this case hot air—rises through the substance with the higher density, the cooler air.

A sample of gas cannot really have a volume of zero because any sample of matter must have some volume.

### Boyle's law - Wikipedia

Note from part a in Figure 6. Similarly, as shown in part b in Figure 6.

Pressure Gases are the only state of matter that can be compressed very tightly or expanded to fill a very large space. Pressure is force per unit area, calculated by dividing the force by the area on which the force acts. The earth's gravity acts on air molecules to create a force, that of the air pushing on the earth.

This is called atmospheric pressure. The units of pressure that are used are pascal Pastandard atmosphere atmand torr. It is normally used as a standard unit of pressure. The SI unit though, is the pascal.

For laboratory work the atmosphere is very large. A more convient unit is the torr.

A torr is the same unit as the mmHg millimeter of mercury. It is the pressure that is needed to raise a tube of mercury 1 millimeter. The Pressure-Volume Law Boyle's law or the pressure-volume law states that the volume of a given amount of gas held at constant temperature varies inversely with the applied pressure when the temperature and mass are constant.

Another way to describing it is saying that their products are constant. When volume goes up, pressure goes down. From the equation above, this can be derived: This equation states that the product of the initial volume and pressure is equal to the product of the volume and pressure after a change in one of them under constant temperature.

For example, if the initial volume was mL at a pressure of torr, when the volume is compressed to mL, what is the pressure? Plug in the values: The Temperature-Volume Law This law states that the volume of a given amount of gas held at constant pressure is directly proportional to the Kelvin temperature. V Same as before, a constant can be put in: