Introductory Gas Laws and Kinetic Molecular Theory

Question-and-answer flashcards covering kinetic molecular theory, pressure units, and fundamental gas laws (Boyle, Charles, Combined, Ideal, and Dalton).

What is meant by an elastic collision in the kinetic molecular theory of gases?

A collision in which gas molecules hit each other and scatter without any net loss of total kinetic energy.

Which four variables are used to describe a gas in the basic gas laws?

Pressure, volume, temperature, and amount (number of moles).

What is the formula for pressure and its value at 1 atmosphere in psi?

Pressure = force ÷ area; 1 atm = 14.7 psi.

How many millimeters of mercury are equal to 1 atmosphere of pressure?

760 mmHg.

What relationship does Boyle’s Law describe between pressure and volume?

They are inversely related

Boyles Law Equation

P₁V₁ = P₂V₂ when temperature and moles remain constan

According to Charles’s Law, how are volume and temperature related for a gas at constant pressure and moles?

They are directly proportional

What temperature conversion must be performed when applying Charles’s Law?

Convert °C to Kelvin by adding 273.

Write the Combined Gas Law and explain when it is used.

(P₁V₁)/T₁ = (P₂V₂)/T₂; used when pressure, volume, and temperature all change for a fixed amount of gas.

State the Ideal Gas Law and give the numerical value and units of R.

PV = nRT; R = 0.0821 L·atm·mol⁻¹·K⁻¹.

When a problem gives grams or moles of a gas, which gas law is most appropriate to use?

The Ideal Gas Law (PV = nRT).

What is Boyles Law

Pressure and Volume are inversely related (with constant temp and number of moles)

Charles Law

Volume and Temp(in Kelvin) are directly related (assuming pressure and number of moles is constant)

Combined Gas Law in words

The product of the pressure and volume of a fixed amount of gas is directly proportional to the Tempurature in Kelvin

Boyles Law

P1V1=P2V2

Charles Law

V1/T1 = V2/T2

Combined Gas Law

P1V1/T1 =P2V2/T2

Ideal Gas Law

PV = nRT

R

0.0821

Daltons Law

Ptotal = P1+ P2 + P3

When do you use Daltons Law

When you see mixture of gas in a container

When do you use Ideal Gas Law

Use this when you see a question with grams or moles

When do you use the Combined Gas Law

Use this when a question has 5 #’s

How do you find K from C

C+ 273

What does Dalton’s Law of Partial Pressures state about a gas mixture?

The total pressure equals the sum of the partial pressures of all component gases (P_total = P₁ + P₂ + …).

How does the vertical movement of air affect atmospheric pressure?

Sinking air increases atmospheric pressure, while rising air decreases it.

What instrument measures atmospheric pressure, and what does it actually measure?

A barometer; it measures the height of a column of mercury that balances the atmospheric pressure.

Boiling Point

The temperature at which a liquid’s vapor pressure equals the external (atmospheric) pressure, causing the liquid to turn into a gas.