In a direct relationship, one variable follows the same change when it comes to increasing and decreasing. For example, when the pressure increases then the temperature also increases. When the pressure decreases, then the temperature decreases.

The pressure law states that for a constant volume of gas in a sealed container the temperature of the gas is directly proportional to its pressure. This can be easily understood by visualising the particles of gas in the container moving with a greater energy when the temperature is increased.

As temperatures increase, additional heat energy is applied to the constituent parts of a solid, which causes additional molecular motion. Molecules begin to push against one another and the overall volume of a substance increases. At this point, the matter has entered the liquid state.

Molality is not effected by temperature as molality is not involved with volume (volume changes with temperature).

(b,d) Both molality and mole fraction are not affected by change in temperature.

Changes in presure have very little effect on the volume of a liquid. Liquids are relatively incompressible because any increase in pressure can only slightly reduce the distance between the closely packed molecules. If the pressure above a liquid is increased sufficiently, the liquid forms a solid.

Pressure: Pressure: Pressure affects the rate of reaction, especially when you look at gases. When you increase the pressure, the molecules have less space in which they can move. That greater density of molecules increases the number of collisions.

Gases are compressible because on applying pressure, the space between the gaseous particles decreases. Therefore, gases can be compressed readily. When we apply pressure and reduce temperature the gases can be converted into liquids i.e., gases will be liquefied.

Factors Affecting Air Pressure:

• Temperature: As the temperature increases, air expands because of which its density decreases which results in low pressure.
• Height from Sea Level:
• Moisture in Air (Humidity):
• Gravitation of Earth:
• Rotation of Earth:

1)The 3 main factors that affect barometric (air) pressure are:

• Temperature.
• Altitude or Elevation.
• Moisture ow water vapour.