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# Can someone tell me about Boyle’s Law & Charles' Law?

Can someone tell me about Boyle’s Law & Charles' Law?

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The Boyles Law

Can be expressed as P1V1=P2V2.

At constant temperature, the pressure is inversely proportional to the volume of a definite amount of gas. This is known as the Boyles law.

Robert Boyles (1627-1691), experimented with gas at constant temperature. Using Torricelli discovery, Boyle measured the variation of pressure when the volume changes, and discovered that volume is inversely proportional to the pressure, and vice versa.

V = kb / P

where kb is a constant. The Boyles law is also part of the ideal gas law, which can be written in the form:

V = n R T / P

At constant temperature, T, this formulation shows that V is inversely proportional to P.

The Charles Law

Can be expressed as V1\V2 =T1\T2.

Jacques Charles (1746-1823) experimented with gas under constant pressure. In today's language, his discovery is that the volume of a gas is proportional to the temperature in K (kelvin).

V = kc T,

where kc is a constant. You should note that the absolute temperature scale (K) must be used for the above formula to be valid.

Again, the Charles's law is also part of the ideal gas law, and the relationship between V and T is obvious:

V = {n R / P} T,

which is the same as the previous one if you assume kc = n R / P

There are four factors that affect gases: pressure, temperature, volume and number of particles.

Boyle (Boyle's Law) investigated the relationship between pressure and volume. To do this he had to keep the temperature and number of particles of gas constant. When he did that he found that the relationship was an INVERSE: when one goes up the other goes down and vice versa. He also discovered that pressure x volume will be a constant value (if temp. and number of particles is constant). The mathematical expression for his law is:

(P1)(V1) = (P2)(V2)

Charles (Charles' Law) investigated the relationship between temperature and volume of a gas. He found that there is a DIRECT relationship between the two if temperature is measured on the Kelvin scale: if one goes up the other goes up and vice versa.

You converst celsius degress to kelvin by adding 273

(Kelvin = celsius + 273)

The mathematical relationship that expresses this law is:

P1/T1 = P1/T2

If you put the two laws together you get what is called the Combined Law. Here you only need the number of particles to be constant. Once again the temperature must be in Kelvin. The combined law is:

(P1)(V1)/(T1) = (P2)(V2)/T2

Boyles Law

1. P1V1=P2V2.

2. pressure of gas is inversely proportional to the volume at constant temperature.

Charles Law

1. V1\V2 =T1\T2.

2. Volume of a gas is proportional to the temperature in K (kelvin) at constant pressure.

Boyle's Law is : Pressure*Volume of gas = Constant

i.e P1V1=P2V2 The graph of Volume Vs Pressure is rectangular hyperbola.

Charle's Law : Volume is directly proportoinal to Temp.

i.e V1\V2 =T1\T2.

Boyle's law (sometimes known as the Boyle Mariotte law) is one of the gas laws. Boyle's Law is named after the Irish natural philosopher Robert Boyle (Lismore, County Waterford,1627-1691) who was the first to publish it in 1662. The relationship was brought to the attention of Boyle by two friends and amateur scientists, Richard Towneley and Henry Power, who discovered it. Boyle confirmed their discovery through experiments and published the results. According to Robert Gunther and other authorities Boyle's assistant Robert Hooke, who built the experimental apparatus, may well have helped to quantify the law; Hooke was accounted a more able mathematician than Boyle. Hooke also developed the improved vacuum pumps necessary for the experiments. The French physicist Edme Mariotte (1620-1684) discovered the same law independently of Boyle in 1676, so this law may be referred to as Mariotte's or the Mariotte Boyle law.

Boyle's Law states that the product of the volume and pressure of a fixed quantity of an ideal gas is constant, given constant temperature. Expressed mathematically, the formula for Boyle's law is:

where:

V is volume of the gas.

p is the pressure of the gas.

k is a constant (see Note 1).

The value of k is computed from measurements of volume and pressure for a fixed quantity of gas. After making a change to the system, typically by forcing a change in the volume of the vessel containing the fixed quantity of gas, the new volume and new pressure are measured. The result of computing the product of the measured new volume and the new pressure should be the original value of the constant k. Without being too rigorous at this point, the equation says that, after forcing the volume V of the fixed quantity of gas to increase, keeping the gas at the initially measured temperature, the pressure P must decrease proportionally. Conversely, reducing the volume of the gas increases the pressure.

Boyle's law is commonly used to predict the result of introducing a change, in volume and pressure only, to the initial state of a fixed quantity of gas. The "before" (subscript 1) and "after" (subscript 2) volumes and pressures of the fixed amount of gas, where the "before" and "after" temperatures are the same (heating or cooling will be required to meet this condition), are related by the equation:

In practice, this equation is solved for one of the two "after" quantities to determine the effect that a change in the other "after" quantity will have. For example:

Boyle's law, Charles's Law, and Gay-Lussac's Law form the combined gas law. The three gas laws in combination with Avogadro's Law can be generalized by the ideal gas law.

Note 1. As long as the constant temperature constraint and the fixed quantity of gas constraint, both explicitly included in the statement of Boyle's law, are not violated, k will be constant.

Charles' law (sometimes called the Law of Charles) is one of the gas laws. It states that at constant pressure, the volume of a given mass of a ideal gas increases or decreases by the same factor as its temperature (in kelvins) increases or decreases.

The law was first published by Joseph Louis Gay-Lussac in 1802, but he referenced unpublished work by Jacques Charles from around 1787. This reference has led to the law being attributed to Charles. The relationship had been anticipated by the work of Guillaume Amontons in 1702.

The formula for the law is:

-where:

V is the volume.

T is the temperature (measured in kelvins).

k is a constant.

To maintain the constant, k, during heating of a gas at fixed pressure, the volume must increase. Conversely, cooling the gas decreases the volume. The exact value of the constant need not be known to make use of the law in comparison between two volumes of gas at equal pressure:

.

Charles's Law, Gay-Lussac's Law, and Boyle's Law form the combined gas law. The three gas laws in combination with Avogadro's Law can be generalized by the ideal gas law.