Question

A) what assumptions characterize an ideal gas?

B)under what conditions are these assumptions most appropriate?

C) what equation describes the thermodynamic state of an ideal gas?

D) if the assumptions os A become inappropriate how do we modify the equation of state to be more realistic?

E) explain from a kinectic theory of particles making up the gas, why doubling the number of moles of a gas doubles the pressure at constant volume and temperature.

F) explain from a kinectic theory of particles making up the gas, why doubling the temperature of a gas doubles the pressure at constant volume and moles

Answer 1

A. The ideal gas law can be derived from the kinetic theory of gases and relies on the assumptions that

(1) the gas consists of a large number of molecules, which are in random motion and obey Newton's laws of motion;

(2) the volume of the molecules is negligibly small compared to the volume occupied by the gas; and

(3) no forces act on the molecules except during elastic collisions of negligible duration.

B. Although no gas has these properties, the behaviour of real gases is described quite closely by the ideal gas law at sufficiently high temperatures and low pressures, when relatively large distances between molecules and their high speeds overcome any interaction.

C.PV=NRT in which R is called the universal gas constant. This constant has been measured for various gases under nearly ideal conditions of high temperatures and low pressures, and it is found to have the same value for all gases: R = 8.314 joules per gram-mole-kelvin.

D.

E.

In physics, pressure, P, is the measure of the force exerted over a certain area. We generally say something exerts a lot of pressure on an object if it exerts a great amount of force on that object, and if that force is exerted over a small area. Mathematically:

Pressure is measured in units of pascals (Pa), where 1 Pa = 1 N/m2.

Pressure comes into play whenever force is exerted on a certain area, but it plays a particularly important role with regard to gases. The kinetic theory tells us that gas molecules obey Newton’s Laws: they travel with a constant velocity until they collide, exerting a force on the object with which they collide. If we imagine gas molecules in a closed container, the molecules will collide with the walls of the container with some frequency, each time exerting a small force on the walls of the container. The more frequently these molecules collide with the walls of the container, the greater the net force and hence the greater the pressure they exert on the walls of the container.Doubling the no of moles of a gas doubles the collission hence doubles the pressure.

f. doubling the temperature increases the speed of collission hence doubles the pressure.