The water inside a kernel of popcorn vaporizes at 180°C, and the resultant gas expands owing to heat until the pressure exceeds nine times that of the atmosphere.

The shell ruptures, and the carbohydrates and proteins in the maize form an inflated, frothy mass.

The connection between a gas's pressure, volume, and temperature are also vital to scuba divers, hot-air balloon operators, and bread bakers, and it is at work during the inflation of a car's airbag, the operation of a car engine, and a variety of other real-world applications.

Throughout history, people have been investigating the behavior of gases and various states of matter.

In reality, three of the ancient Greeks' four "elements" were air (gas), water (liquid), and soil (solid). Nonetheless, despite millennia of observations, many questions remain unanswered.

Gases are all around us. Our atmosphere is a colorless, odorless mixture of 18 gases, several of which—O2, N2, H2O vapor, and CO2—play important roles in the environment's life-sustaining redox processes. Several other gases, such as chlorine and ammonia, are also important in manufacturing.

The chemical activity specific to each gas is ignored in favor of focusing on the physical behavior shared by all gases.

Under the right pressure and temperature circumstances, most substances may exist as a solid, a liquid, or a gas.

Because its particles are wide apart and move randomly, a gas takes on the shape of a container and fills it. Because its particles are so small, a liquid takes on the form of a container to the degree of its volume.

They remain near yet have the freedom to roam around each other. Because its particles have a set form, a solid has a definite shape regardless of the container shape, is close together, and tightly kept in place.

Several more characteristics separate gases from liquids and solids: The volume of a gas varies dramatically as pressure increases.

When a gas sample is confined to a variable volume container, such as a cylinder with a piston, increasing the force on the piston reduces the gas volume; therefore, gases are compressible—the gas particles may be pushed closer together into a smaller volume.

When the external force is removed, the volume can be increased again. Compressed air with a jackhammer smashes rock and cement; compressed air in tires raises the weight of an automobile. Liquids and solids, on the other hand, have extremely little or no compressibility.

The volume of a gas changes dramatically with temperature. When a gas sample is heated, it expands; when it is cooled, it contracts.

Gases have a volume change that is 50 to 100 times higher than liquids or solids. the growth that takes place when rapidly heated gases may have dramatic consequences, such as launching a rocket into space and commonplace ones, such as popping corn.

Gases move extremely quickly. Gases move significantly faster than liquids and solids.

This characteristic allows gases to be carried more readily via pipes, but it also has a negative impact.

This means they leak more quickly via tiny holes and fractures.

The densities of gases are low. Gas density is often measured in grams per liter (g/L), whereas liquid and solid densities are measured in grams per milliliter (g/mL), which is almost 1000 times as dense (see Table 1.5).

For instance, have a look at the table comparing the densities of a gas, liquid, and solid at 20°C and normal pressure in the atmosphere. When a gas cools, its density rises because its volume decreases, when the temperature drops from 20°C to 0°C, the density of O2(g) rises from 1.3 to 1.4 g/L.

Gases can combine to produce a solution in any proportion. Air is a mixture of 18 gases. However, two liquids may or may not form a solution: water and ethanol, but not water and gasoline.

Unless two substances are melted, they will not create a solution and combine while liquids, then allowed to harden (as in the alloying process).

These macroscopic properties—changing volume with pressure or temperature, tremendous ability to flow, low density, and capacity to form solutions, similar to how a gas entirely fills a container—arise because the particles in a gas are considerably further apart than those in a liquid or a solid at normal pressures.

The volume of a gas can be dramatically changed by varying the applied force or temperature.

For liquids and solids, the corresponding changes are significantly less. Gases are less dense and flow more easily than liquids and solids.

Gases can combine in any proportion to produce solutions; liquids and solids, on the other hand, can not. Differences in physical states are caused by a larger average distance between particles in gas as opposed to a liquid or solid.

Gas particles travel at relatively high speeds within a container, hitting often the container's walls.

The force of these collisions with the walls, known as gas pressure, is what allows you to blow up a balloon or pump up a tire. The force exerted per unit of the charge a bond surface area is denoted as pressure (P):

• pressure = force/area

The gases in the atmosphere exert a consistent force (or weight) on all surfaces, resulting in atmospheric pressure, which is generally around 14.7 pounds per square inch (lb/in2); psi) of surface pressure. As a result, a pressure of 14.7 lb/in2 is obtained.

The pressure on the exterior of your room (or your body) matches the pressure on the inside.