BOYLE LAW

CHAPTER I

INTRODUCTION

A. Background

Gas is a substance which molecules or particles move freely. in this chapter will be studied on the microscopic properties of a gas with a review of the pressure, volume and temperature is often called the kinetic theory of gases. otherwise it will be studied also the science of energy is often called thermodynamics, which specifically discusses the relationship between heat energy to work. energy can be transformed from one form to another, either naturally or the result of engineering technology. besides the energy in the universe is eternal, can not be raised or eliminated, what happens is a change of energy from one form into another form without any reduction or increase. it is closely connected with the law - the basic law of the thermodynamics.

B. Problem formulation

Then the problem is formulated as follows:

What is the ideal gas equation of kinetic theory?

What is the sense and the laws of thermodynamics?

C. Purpose

writing of this paper are expected to provide the following benefits:

Provide additional knowledge to the reader about the ideal gas equation of kinetic theory.

Provide an explanation of things - the basic thing that is often overlooked in thermodynamics.

Provide knowledge and understanding to the reader about the laws of thermodynamics.

CHAPTER II

DISCUSSION

A. Kinetic Theory of Ideal Gas

In this case the so-called ideal gas is a gas that meets the following assumptions:

Consists of particles in large numbers and no force of attraction antarpatikel

Each gas particle is always moving in random directions (arbitrary)

Negligible particle size to the size of the container

Each collision is occurring perfectly resilient.

Gas particles distributed uniformly in the entire space in the container.

Motion of gas particles meet newton laws of motion.

Based on the experimental equation of state of gas that has been done by changing the amount of pressure, volume, and temperature was no proportionality between the product of pressure and volume to temperature as follows:

PV? T

as well as the mass of the gas system after varied with the pressure, volume, and temperature of proportionality are as follows:

PV? MT

to make the above equation to be perfect it would require a constant comparison of equal value to all gas. of the experimental results of the constant comparison is different for each gas if we use mass units but using mol. 1 mole is defined as the amount of substance contained in 12 grams of carbon-12 atoms which is about 6.02 x 1023 particles. 6.02 x 1023 numbers called numbers avogrado (na)

mole of a substance can thus be expressed in the number of particles n as follows:

n = or n = n na

with

n = amount of substance (mol)

n = number of particles (molecules)

na = number avogrado (6.02 x 1023)

universal constant of proportionality, which applies to all gas is r (universal gas constant) so that the ideal gas equation of state can be written as follows widened.

PV = nRT

with

p = gas pressure (atm or N/m2)

v = volume of gas (m3 or liter)

n = number of moles of gas (mol)

r = the universal gas tetapam (8.31 j / mol k)

t = temperature of gas (k)

therefore n = the ideal gas equation of state can be expressed in a number of molecules.

pv = rt

pv = NKT

with Boltzmann constant k == (1.38 × 10-23 j / k)

p = gas pressure (N/m2)

v = volume of gas (m3)

n = number of molecules

t = temperature of gas (k)

when viewed from a microscopic point of view, the particles exert a force of mutual attraction of substances derived from the electrical properties and gravity (Newton's law of gravity). in addition there is also a pull force antarpartikel antarpartikel repulsive force emanating from the electrical properties of atomic nuclei are positively charged. atomic mass centered on the nucleus, so Juka atomic distances are too close there will be a significant repulsive force of the atoms. thus, there is a minimum distance that must be maintained by the atoms in order to avoid the repulsive force.

ideal gas equation of state

ideal gas equation is an equation that menyetakan relationship between pressure, volume, and temperature of a gas. The following equations are found in the laws of physics.

Boyle's law

Boyle's law which says if the mass and temperature of a gas is kept constant then the volume of gas will be inversely proportional to absolute pressure, which is proposed by Robert Boyle (1627-1691).

caption =

Another statement of Boyle's law is that the time between pressure and volume will be a constant value for the mass and the gas temperature is maintained constant. can be written mathematically

pv = c

caption =

gas pressure p = (n / m 2 or pa)

v = volume of gas (m3)

c = constant is dimensionless business

examples of questions

contained in a 4 liter container of gas with a pressure of 4 atm and a temperature of 470c. then the gas pressure to 1/4 of its original pressure and gas temperature is maintained constant. what is the volume of gas now?

discussion:

p1 = 4 atm of Boyle's law, at fixed temperature relationship

¼ p1 = p2 = 1 atm applies are: p1.v1 = p2.v2

t = 470c v2 ==

v1 = 4L = 16 liters

v2 = ....? so, now is the gas volume of 16 liters.

charles law

charles law reads gas volume is directly proportional to absolute temperature, during the mass and the gas pressure is maintained constant, expressed by jacques charles 1787. thus the volume and temperature of a gas at constant pressure is directly proportional and the proportionality can be written mathematically as follows.

v = kt, where k is a constant

then to the gas in a container volume and temperature changes from state 1 to state 2 when the pressure is maintained constant and mass, can be formulated following:

=

by v1 = initial volume of gas (m3)

v2 = final gas volume (m3)

t1 = initial gas temperature (k)

t2 = final gas temperature (k)

examples of questions

gas in an enclosed space has a volume of 1 liter at a pressure of 10 atm and temperature of 470c. gas is heated at a constant pressure so that the temperature be 770c. what is the volume of gas now?

discussion

p = 10 atm at a constant pressure force relationship as follows.

v1 = 1l =

t1 = 470c = 320 k = 1.094 liter è == v2

t2 = 350 k = 770c so, now is the gas volume of 1.094 liter

Gay Lussac law

at constant volume, gas pressure is directly proportional to absolute temperature of the gas. relationship is known as Gay-Lussac's law, expressed by joseph gey Lussac (1778-1850). mathematically written as follows:

or p = c.t

= C ===> v = fixed

for gas in a container that had kept warm by volume, at the 1 and 2 gey Lussac law can be written as follows:

====> V = fixed

with p1 = initial pressure (atm)

p2 = the final pressure (atm)

t1 = initial absolute temperature (k)

t2 = final temperature (k)

examples of questions

gas in an enclosed space has a volume of 2.5 liters, 2 atm pressure, and temperature of 270c. what is the gas pressure if the temperature is increased to 670c in fixed volume?

discussion:

v = 2.5 l in volume gey Lussac law remains in force,

p1 = 2 atm ===> p1 == p2 => p2 = x 2

t1 = 270c = 300k p2 = 2.27 atm

t2 = 670c = 340K so, the gas pressure at a temperature of 670c is 2.27 atm

Boyle-Gay Lussac law

a formula derived from the development of the law of Boyle and Gay Lussac equation of state of gas is a more general scale connecting pressure, volume, and temperature in various keadaaa, so as to obtain the following equation:

= C if the two states then can be written as =

information

p1 = initial gas pressure (N/m2)

v1 = initial volume of gas (m3)

t1 = the absolute temperature of gas at first (k)

p2 = the final gas pressure (N/m2)

v2 = final gas volume (m3)

t2 = the absolute temperature of the end gas (k)

examples of questions

the density of a gas at temperature T and pressure p is p. if the gas pressure is used as the 2p and the temperature was lowered to 0.5 t. determine the density of the end?

discussion:

p1 = p

p2 = 2p

t1 = t

t2 = 0.5 t

v1 =

v2 =

theory of thermodynamics

on the thermodynamics of the process there are four isobaric, isothermal, iskhorik, adiabatic. these processes are used in the law of thermodynamics i.

isobaric process (constant pressure)

in the isobaric process, the system pressure be kept constant. because the pressure is constant, then the energy change in (delta u), heat (q) and work (w) in the isobaric process no one is zero. thus, the equation of the first law of thermodynamics remains intact as before:

gas pressure and volume changes in isobaric process is described by the graph below:

first volume of the system = v1 (small volume). because the pressure be kept constant after the heat added to the system, the system expands and does work on the environment. after doing work on the environment, the volume of the system changed to v2 (the system volume increases). the amount of work (w) is performed by the system = the shaded area.

the isothermal (constant temperature)

in the isothermal process, the system temperature be kept constant, the temperature of an ideal gas is directly proportional to the energy in an ideal gas (u = 3/2 NRT). because t does not change then u is not changed. thus, if applied to the isothermal process, the first law of thermodynamics equation will change shape like this:

of these results, we can conclude that in the isothermal (constant temperature), heat (q) is added to the system used the system to perform the work (w).

pressure and volume changes in the process of isothermal systems described by the graph below:

first volume of the system = v1 (small volume) and the system pressure = p1 (pressure). so that the system temperature constant after the heat added to the system, the system expands and does work on the environment. once the system does work on the environment, the volume of the system changed to v2 (the system volume increases) and the pressure turns into p2 system (the system pressure is reduced). curved graph form as the system pressure does not change regularly during the process. amount of work done = area of ​​the shaded system.

isokorik process (constant volume)

isokorik process, the system volume be kept constant. then the system can not perform work on the environment. vice versa, the environment can not do the work in the system.

if applied to the process isokorik, the first law of thermodynamics equation will change shape like this:

of these results, we can conclude that the process isokorik (constant volume), heat (q) is added to the system used to raise the energy in the system.

pressure and volume changes in the system isokorik illustrated by the graph below:

initial system pressure = p1 (small pressure). the addition of heat to the system causes the energy in the system increases. because the energy in the system increases the temperature of the system (ideal gas) increases (u = 3/2 NRT). temperature is directly proportional to pressure. Therefore, if the system temperature increases, the system pressure increases (p2). because the volume of the system is always constant, there is no work done (no shaded area).

adiabatic process

adiabatic process, no heat is added to the system or leave the system (q = 0). adiabatic process can occur in a closed system that is well insulated. for a closed system that is well insulated, usually with no heat flow into the system arbitrarily or leave the system. adiabatic process can also occur in a closed system is not isolated. for this case, the process must be done very quickly so the heat could not flow into the system or leave the system.

if applied to the adiabatic process, the first law of thermodynamics equation will change shape like this:

if the system is rapidly suppressed (work done on the system), then the work is negative. because w is negative, then u is positive (energy in the system increases). otherwise if the system or expands rapidly expanding (the system does work), then w is positive. because w is positive, then u is negative (energy in the system is reduced).

energy in the system (ideal gas) is proportional to temperature (u = 3/2 NRT), hence if the energy in the system increases, the system also increases. conversely, if the energy in the system reduced the system temperature is reduced.

pressure and volume changes in the adiabatic system described by the graph below:

adiabatic curve on this graph (curves 1-2) is steeper than the isothermal curves (curves 1-3). steepness of this difference suggests that for the same increase in volume, the system pressure is reduced more in the process of adiabatic than isothermal process. system pressure is reduced more in the process adiabatic because when the adiabatic expansion, the temperature of the system is also reduced. temperature is proportional to the pressure, so when the system temperature decreases, the system pressure is also reduced. vice versa in isothermal process, the temperature of the system is always constant. thus the isothermal process the temperature does not influence the pressure drop.

bibliography

hilman, setiawan. 2007.fisika for sma and ma xi class. Dharma kalokatama.jakarta devices.