Gas Laws Part 3 (Gay Lussac's Law, Avogadro's Law, and Ideal Gases)

States that the pressure exerted by a gas (of a given mass and kept at a constant volume) varies directly with the absolute temperature of the gas. In other words, the pressure exerted by a gas is proportional to the temperature of the gas when the mass is fixed and the volume is constant.

Gay Lussac’s Law

-This law was formulated by the French chemist Joseph Gay-Lussac in the year 1808. The mathematical expression of Gay-Lussac’s law can be written as follows:

P ∝ T ; P/T = k

is the pressure exerted by the gas

is the absolute temperature of the gas

is a constant

P

T

k

The pressure of a gas increases as its temperature increases, assuming constant mass and volume

Gay-Lussac’s Law

Decreases pressure

Decreasing Temperature

Increases pressure

Increases temperature

From the graph, it can be understood that the pressure of a gas (kept at constant volume) reduces constantly as it is cooled until the gas eventually undergoes ________ and becomes a liquid.Fo

condensation

Formula for Gay Lussac’s Law

P1T2=P2T1

When volume is constant, this equation is used to compare different conditions on the same substance

P1/T2 = P1/T2

Pressure is directly proportional to temperature

P ∝ T

Pressure divided by temperature equals the k constant

P/T = k

Rules for counting significant figures

All non-zero digits and any zeros contained between non-zero digits count

Leading zeros don’t count

Trailing zeroes count if there is a decimal point

Trailing zeros may or may not count if there is no decimal point, so we go with the most conservative answer

The combined gas law combines the three gas laws: ____________t states that the ratio of the product of pressure and volume and the absolute temperature of a gas is equal to a constant. When Avogadro's law is added to the combined gas law, the ideal gas law results.

Boyle's Law, Charles' Law, and Gay-Lussac's Law. I

Combined Gas Law Formula

P1V1T2=P2V2T1

Boyle’s Law

PV = k

Charles’ Law

V/T = k

Gay-Lussac’s Law

P/T = k

Combined Gas Law

PV/T = k

The _______ is a combined set of gas laws that is a thermodynamic equation that allows us to relate the temperature, volume, and number of molecules (or moles) present in a sample of a gas. The ideal gas law was discovered by physicist and engineer Benoît Paul Émile Clapeyron in 1834.

ideal gas law

______ are the gases which have elastic collisions between their molecules and there are no intermolecular attractive forces. In reality, there is no such thing as ideal gases. The gases just show ideal behaviour under certain conditions of temperature and pressure.

Ideal gases

When we talk about ideal gases, the following assumptions are taken into consideration

The ideal gases are made up of ______ that are in constant motion in random directions.

The molecules of an ideal gas behave as ______

molecules

rigid spheres.

All the collisions are _____

The temperature of the gas is directly proportional to the ____________

Pressure occurs due to the collision between the molecules with the walls of the container.

elastic

average kinetic energy of the molecules.

Ideal Gas Law Formulas

PV = nRT whereas:

P is pressure measured in atmosphere

V is volume measured in Liters

n is moles of gas present

R is constant that converts the units. Its value is 0.0821 atm.L /mol.K

T is temperature measured in Kelvin

p = nRT/V

V = nRT

n = PV

T = PV/nR

R = PV/nT

_______ equal volumes of any gas at the same temperature and pressure contain the same number of molecules. It follows that the volume of a gas is directly proportional to the number of moles of gas present in the sample.

Avogadro's hypothesis:

Amedeo Avogadro law

_________ states that the volume of a gas is directly proportional to the number of moles of gas, when the temperature and pressure are held constant.

Avogadro's Law

The mathematical expression of Avogadro's Law is:

_________________

(Where n is the number of moles of gas and k is a constant). Avogadro's Law is in evidence whenever you blow up a balloon. The volume of the balloon increases as you add moles of gas to the balloon by blowing it up.

V=k×n and V1/n1=V2/n2

When temperature and pressure are constant, this equation is used to compare different situations on the same substance

V1/N1 = V2/N2

Volume is directly proportional to the amount of gas in moles

V ∝ N

Volume divided by the amount of gas equals the k constant

V/N = k

Equal volumes of a gas contain the same number of molecules at the same temperature and pressure

Avogadro’s Law

It doubles the pressure

Doubling the number of molecules