Year 11 chemistry module 2.4

Gas Laws

Whate are gas laws?

The relationship between the temperature, pressure, volume and number of moles of a gas. They are a set of fundamental principles that describe the behaviour of ideal gases.

What is pressure?

The force exerted by gas or liquid particles colliding with the walls of their container, typically calculated as the SI unit of pressure which is pascal (Pa) or kilo-pascal (KPa)

What is atmospheric pressure?

The force exerted by the weight of Earth’s air pushing down on a surface, caused by gas molecules colliding with objects.

What is standard temperature and pressure (STP)?

A set of conditions used as a baseline for measuring and comparing the properties of gases. The standard temperature is typically utilised in the units of Kelvin, where 0 C equals 273.15K. The standard pressure is 1 atmospheres which is equal to 100 KPa.

What are standard laboratory conditions?

Defined as a temperature of 25 degrees celsius or 298.15 K and a pressure of 100kPa. Designed to mimic a practical, comfortable room-temperature workspace where most chemical reactions take place.

What is ideal gas?

A theoretical model of a gas composed of randomly moving point particles that have no volume and do not interact with each other. The ideal gas law is PV = nRT where P is pressure measured in atmosphere, V is volume in liters, n is moles of gas pressure, R is the constant of variation, and T is the temperature measured in Kelvin.

What does Gay Lussac’s Gas Law state?

As the temperature, T, of a gas increases, the pressure, P, of the gas increases. Therefore, P and T are directly proprtional.

What two things does Gay Lussac state have a direct relationship in his gas law?

Temperature and pressure

What is the formula(s) for Gay Lussac’s Gas law (The law of pressure)?

P1/T1 = P2/T2

OR

P/T = K , where k is a constant at a given pressure.

Using Gay Lussac’s law, how can you find the temperature after the increase in pressure (T2) by rearranging the formula P1/T1 = P2/T2

P2 x T1 / P1

Using Gay Lussac’s law, how can you find the pressure after the increase in Temperature (P2) by rearranging the formula P1/T1 = P2/T2?

P1/T1 x T2

Using Gay Lussac’s law, how can you find the initial temperature (T1) by rearranging the formula P1/T1 = P2/T2

P2 x T2 / P1

Using Gay Lussac’s law, how can you find the initial pressure (P1) by rearranging the formula P1/T1 = P2/T2?

P2 / T1 x T2

What does Gay Lussac’s Law of Combining Volumes state?

The volumes of gases that react with one another, or are produced in a chemical reaction, are in the ratio of small integers, provided that all the gases are at the same temperature and pressure.

What does Boyle’s gas law state?

The volume of a gas is inversely proprtional to its pressure, provided that the temperature and the number of moles of gas are constant.

What factors are involved in Boyle’s Gas Law?

Pressure and volume

What is the formula(s) for Boyle’s gas law?

PV = k

OR

P1V1 = P2V2

OR

P inversely proprtional 1/V

Using Boyle’s gas law, how can you find the pressure after the increase in volume (P2) by rearranging the formula P1V1 = P2V2?

P1 x V1 / V2

Using Boyle’s gas law, how can you find the volume after the increase in pressure (V2) by rearranging the formula P1V1 = P2V2?

P1 x V1 / P2

Using Boyle’s gas law, how can you find the initial pressure (P1) by rearranging the formula P1V1 = P2V2?

P2 x V2 / V1

Using Boyle’s gas law, how can you find the initial pressure (P1) by rearranging the formula P1V1 = P2V2?

P2 x V2 / P1

What does Charles’ Gas Law state?

The volume of any gas increases linearly with increasing temperature when the pressure and the quantity of gas (the number of moles of gas) are held constant.

What are the formula(s) for Charles’ gas law?

V Inversely proportional T

Or

V1/T1 = V2/T2

Or

V/T = K

Using Charles’ gas law, how can you find the volume after increasing the temperature (V2) using the formula V1/T1 = V2/T2?

V1/T1 x T2

Using Charles’ gas law, how can you find the temperature after increasing the volume (T2) using the formula V1/T1 = V2/T2?

V2 x T1 / V1

Using Charles’ gas law, how can you find the initial volume (V1) using the formula V1/T1 = V2/T2?

V2 x T1/ T2

Using Charles’ gas law, how can you find the initial temperature (T1) using the formula V1/T1 = V2/T2?

V1 x T2 / V2

What does Avogadro’s gas law state?

The volume of a gas is directly prprtional to the number of moles of a gas, if the temperature and pressure are constant.

What are the formula(s) for Avogadro’s gas law?

V/n = k

OR

V inversely proprtional n

OR

V1/n1 = V2/n2

In Avogadro’s gas law, what does the n stand for?

The amount of gas in moles

Using Avogadro’s gas law, how can you find the initial volume (V1) by rearranging the formula V1/n1 = V2/n2?

V2 x n1 / n2

Using Avogadro’s gas law, how can you find the initial moles of gas (n1) by rearranging the formula V1/n1 = V2/n2?

V1 x n2 / V2

Using Avogadro’s gas law, how can you find the final volume (V2) by rearranging the formula V1/n1 = V2/n2?

V1 x n2 / n1

Using Avogadro’s gas law, how can you find the final moles of gas (n2) by rearranging the formula V1/n1 = V2/n2?

n1 x V2 / V1

What does Avogadro’s molar volume of a gas state?

If the amount of gas is fixed at 1 mole, the volume it occupies depends most entirely on its temperature and pressure

What is the molar volume, Vm, of a gas?

The amount of space, or volume, occupied by 1 mole of any gas at a particular pressure and temperature. The volume of 1 mole of gas, Vm, is equal to its total volume, V, divided by the number of mles, n, of gas present.

What is the formula for the molar volume of a gas?

Vm = V/n

What is the combined gas law?

all 3 gas laws conveniently combined to create a relationship between P, V, and T.

What are the formula(s) for the combined gas law?

PV/T = k

OR

P1V1/T1 = P2V2/T2

True or False: The ideal gas law and combined gas law are the same thing.

False: they are not the same thing.

Why was the ideal gas law created?

Avogadro’s law, Boyle’s law, and Charles’ law are all obeyed very closely, but not exactly, by real gases at temperatures close to or above room temperature and at pressures below a few atmospheres (100 kPa)

What is the ideal gas law?

A single equation that describes the way the volume depends on all three variables of gases.

What is the formula for the ideal gas law?

PV = nRT - where R is the universal gas constant.

What is the value of R (constant) in the ideal gas law?

8.314 if pressure is in kPa, volume is in L, and temperature is in Kelvin.