Chemistry Matters

Combined and Ideal Gas laws: The Real Deal!

2012-03-11T11:24:00.000-07:00

Combined and ideal gas laws

BLOGGER NO. 3

With the addition of Avogadro's law, the combined gas law develops into the ideal gas law:

where

P is pressure
V is volume
n is the number of moles
R is the universal gas constant
T is temperature (K)
where the constant, now named R, is the gas constant with a value of .08206 (atm∙L)/(mol∙K).

An equivalent formulation of this law is:

where
P is the absolute pressure
V is the volume
N is the number of gas molecules
k is the Boltzmann constant (1.381×10−23 J·K−1 in SI units)
T is the temperature (K)

These equations neglects various intermolecular effects which are exact only for an ideal gas . However, the ideal gas law is a good approximation for most gases under moderate pressure and temperature.
This law has the following important consequences:

If temperature and pressure are kept constant, then the volume of the gas is directly proportional to the number of molecules of gas.
If the temperature and volume remain constant, then the pressure of the gas changes is directly proportional to the number of molecules of gas present.
If the number of gas molecules and the temperature remain constant, then the pressure is inversely proportional to the volume.
If the temperature changes and the number of gas molecules are kept constant, then either pressure or volume (or both) will change in direct proportion to the temperature.

We the Blogging team hope that with the help of our blog, it would be much easier to understand Combined and Ideal Gas laws. :)

Charles's law: The temperature-Volume relationship.

2012-02-28T06:53:00.000-08:00

Charles's law

Blogger no 3:

Charles's Law, or the law of volumes, was found in 1678. It says that, for an ideal gas at constant pressure, the volume is directly proportional to the absolute temperature (in kelvins).

Where T is the absolute temperature of the gas (in kelvins) and k₂ (in m³·K⁻¹) is the constant produced.

Charles' Law describes the direct relationship of temperature and volume of a gas. Assuming that pressure does not change, a doubling in absolute temperature of a gas causes a doubling of the volume of that gas. A drop of absolute temperature sees a proportional drop in volume. The volume of a gas increases by 1/273 of its volume at 0°C for every degree Celsius that the temperature rises.

In other words :

Graphically Charles law can be made as:

We The Bloggers hope that now it would be much easier to understand Charles Law. Happy reading. :)

Boyle's Law: A closer look.

2012-02-25T23:39:00.003-08:00

Boyle's law
Blogger no. 3:

Boyle's law shows that, at constant temperature, the product of an ideal gas's pressure and volume is always constant. It was published in 1662. It can be determined experimentally using a pressure gauge and a variable volume container. It can also be found through the use of logic; if a container, with a fixed number of molecules inside, is reduced in volume, more molecules will hit the sides of the container per unit time, causing a greater pressure.

As a mathematical equation, Boyle's law is:

where k is the constant of proportionality and its value is 1

Where P is the pressure (Pa), V the volume (m³) of a gas, and k₁ (measured in joules) is the constant from this equation.

Also remember that :

Graphically, we can show Boyle's Law by the graph below:

we the bloggers hope that our contribution is helpful for you to understand Boyle's Law more easily.

Kinetic Molecular Theory!

2012-02-24T12:52:00.000-08:00

Kinetic Molecular Theory

Blogger no.3:

Basic Concepts

The gas laws developed by Boyle, Charles, and Gay-Lussac are based upon empirical observations and describe the behavior of a gas in macroscopic terms, that is, in terms of properties that a person can directly observe and experience. An alternative approach to understanding the behavior of a gas is to begin with the atomic theory, which states that all substances are composed of a large number of very small particles (molecules or atoms). In principle, the observable properties of gas (pressure, volume, temperature) are the consequence of the actions of the molecules making up the gas.

The Kinetic Molecular Theory of Gases begins with five postulates that describe the behavior of molecules in a gas. These postulates are based upon some simple, basic scientific notions, but they also involve some simplying assumptions. In reading a postulate, do two things. Firstly ,try to understand and appreciate the basic physical idea embodied in the postulate. This idea will ultimately be important in understanding the macroscopic properties of the gas in terms of the behavior the microscopic molecules making up the gas. Second, identify possible weakness or flaws in the postulates. Inaccurate predictions by a theory derive from flawed postulates used in the derivation of the theory.

Postulates

· A gas consists of a collection of small particles traveling in straight-line motion and obeying Newton's Laws.

· The molecules in a gas occupy no volume (that is, they are points).

· Collisions between molecules are perfectly elastic (that is, no energy is gained or lost during the collision).

· There are no inter molecular force of attraction or repulsion between the molecules.

· The average kinetic energy of a molecule is 3kT/2. (T is the absolute temperature and k is the Boltzmann constant.)

We hope that understanding Kinetic molecular theory now would be much more easier with the help of our blog. :)

We: The Bloggers!

2012-02-21T06:52:00.001-08:00

This blog is made by our group of five members and we are AKHSSIAN'S:

Hey friends, this is Kashaf Zehra and I am Blogger no. 1! I was born on 4th February 1996. I grew up in Karachi. I have done my matriculation from Aga Khan School with good grade. I took an admission in AKHSS for my higher studies due to its reputation and educational standard.....I possess some characteristics like i am confident, humble, cooperative, sincere with my aims, social, straight forward. During my elementary school I had achieved a lot in different activities like won several times in poster making competitions and Science Olympiads e.t.c ....Although I'm studying in Pre-medical department, but my passion is to become a fashion designer because I feel that creativity is in my blood. Mentioning my hobbies; I love reading, sketching, painting and gossiping with friends.I wish my contribution for making this site will help you in basic concept making.

Hi everyone, i am Ruhiya Altaf studying in Aga Khan Higher Secondary School and I am Blogger no. 2. I was born on 5th December 1995 and so now i am 16. I finished my schooling with honors and awards at Habib Girls School. This where I learned playing musical instruments- throw ball, pottery and I discovered and uncovered my different talents. I am good at english and I love to read specific novels and partying with friends.I have very high aims and I really have to work hard to achieve them. I am a work in progress, may God be praised.

Bonjour lovely readers! My name is Warda Jaffri and I am Blogger no. 3! I came in this world on the 25^th of April,1995. Since birth, I've been living in Karachi, Pakistan. Did my matriculation From one of the most prestigious Schools of Karachi, Habib Girls’ School! Currently I am studying in Aga Khan Higher Secondary School, Pre-medical department. I personally have a lot of dreams that I wish to accomplish in future. I want to do M.B.B.S and further bachelors in Forensic Sciences and Criminology and aim for a job in FBI :) . I'm a fun loving person who likes to party hard! I'm EXTREMELY SPORTY! i love freelance writing, Digital photography and I'm also a social Activist. Also i have an undying love for Chemistry! We, the blogging team hope that our blog help you guys out in clearing your concepts regarding chemistry. so have a happy time viewing our blog!

Assalamwalikum ...Namastay.....Hey........ Hello...... Chemistry lovers .......=)...My name is Muhammad Shahzad Samad and and I am Blogger no.4 !!! I was born on 12th june 1993 in Karachi. I am 18 years old and currently studying in Aga khan Higher Secondary School, Pre-medical Department. I studied at Falcon House Grammar School during General Certifcate of Education ( GCE "O" Levels).I love to play cricket and acting is my passion.I am a member of dramatics in Akhss. My hobby is to watch movies and television series. I am friendly, have sense of humor =) , extremely talented and believes that no one can steal talent from anyone.I try to utilize most of my time in doing something constructive. According to me , everyone in this world has his/her own school of thoughts.I believe we students should help each other regarding studies in any possible way we find.So sharing information regarding Chemistry on blog is one of the best way to facilitate and ease the pressure on students.My friends Chemistry is a very interesting subject if you try to find it interesting.I hope you all like our efforts and service to help students regarding chemistry!!!