Properties of Liquids

Properties of Liquids

Basic Temperature and Critical Pressure 

The undeniable method to transform a gas into a fluid is to cool it to a temperature underneath its breaking point. There is another method for gathering a gas to shape a fluid, be that as it may, which includes raising the weight on the gas. Liquids bubble at the temperature at which the vapor weight is equivalent to the weight on the fluid from its environment. Raising the weight on a gas in this way viably builds the breaking point of the fluid.

Assume that we have water vapor (or steam) in a shut holder at 120oC and 1 atm. Since the temperature of the framework is over the typical breaking point of water, there is no explanation behind the steam to consolidate to shape a fluid. Nothing occurs as we gradually pack the holder - in this way raising the weight on the gas- - until the weight arrives at 2 atm. Now, the framework is at the breaking point of water, and a portion of the gas will consolidate to shape a fluid. When the weight on the gas surpasses 2 atm, the vapor weight of water at 120oC is never again huge enough for the fluid to bubble. The gas along these lines gathers to shape a fluid, as appeared in the figure underneath.

In principle, we ought to have the option to foresee the weight at which a gas gathers at a given temperature by counseling a plot of vapor weight versus temperature . By and by, each compound has a basic temperature (Tc). In the event that the temperature of the gas is over the basic temperature, the gas can't be dense, paying little respect to the weight applied.

The presence of a basic temperature was found by Thomas Andrews in 1869 while concentrating the impact of temperature and weight on the conduct of carbon dioxide. Andrews found that he could gather CO2 gas into a fluid by raising the weight on the gas, as long as he kept the temperature underneath 31.0oC. At 31.0oC, for instance, it takes a weight of 72.85 atm to liquify CO2 gas. Andrews found that it was difficult to transform CO2 into a fluid over this temperature, regardless of how much weight was applied.

Gases can't be liquified at temperatures over the basic temperature in light of the fact that now the properties of gases and liquids become the equivalent, and there is no premise on which to recognize gases and liquids. The vapor weight of a fluid at the basic temperature is known as the basic weight (Pc). The vapor weight of a fluid never gets bigger than this basic weight.

The basic temperatures, basic weights, and breaking points of various gases are given in the table beneath. There is an undeniable connection between's the basic temperature and breaking point of these gases. These properties are connected in light of the fact that they are both aberrant proportions of the power of fascination between particles in the gas stage.

Basic Temperatures, Critical Pressures and Boiling Points of Common Gases

Gas Tc(oC) Pc (atm) BP (oC)

He -267.96 2.261 -268.94

H2 -240.17 12.77 -252.76

Ne -228.71 26.86 -246.1

N2 -146.89 33.54 -195.81

CO -140.23 34.53 -191.49

Ar -122.44 48.00 -185.87

O2 -118.38 50.14 -182.96

CH4 -82.60 45.44 -161.49

CO2 31.04 72.85 -78.44

NH3 132.4 111.3 -33.42

Cl2 144.0 78.1 -34.03

The trial estimations of the basic temperature and weight of a substance can be utilized to ascertain the an and b constants in the van der Waals condition.

conditions

Weight versus Force 

The volume of a gas is one of its trademark properties. Another trademark property is the weight the gas applies on its environment. A considerable lot of us got our first presentation to the weight of a gas when we rode to the local service station to check the weight of our bike tires. Contingent upon the sort of bike we had, we added air to the tires until the weight measure read somewhere in the range of 30 and 70 pounds for every square inch (lb/in2 or psi). Two significant properties of weight can be acquired from this model.

1. The weight of a gas increases as more gas is added to the holder.

2. Weight is estimated in units, (for example, lb/in2) that portray the power applied by the gas isolated by the zone over which this power is circulated.

The main end can be outlined in the accompanying relationship, where P is the weight of the gas and n is the measure of gas in the holder.

P proportional n 

Since the weight increments as gas is added to the compartment, P is straightforwardly relative to n.

The subsequent end portrays the connection among weight and power. Weight is characterized as the power applied on an article partitioned by the zone over which the power is dispersed.

The distinction among weight and power can be delineated with a similarity dependent on a 10-penny nail, a sledge, and a bit of wood appeared in the figure underneath. By laying the nail on its point, and hitting the head with the mallet, we can drive the nail into the wood. In any case, what occurs in the event that we turn the nail over and rest the leader of the nail against the wood? In the event that we hit the nail with a similar power, we can't get the nail to stick into the wood.