Gas Laws Round 1 Flashcards
What is the general gas equation?
PV = nRT, where P = pressure, V = volume, n = moles, R = gas constant, and T = temperature.
Define Boyle’s Law.
Boyle’s Law states that at a constant temperature, the pressure of a gas is inversely proportional to its volume (P1V1 = P2V2).
Define Charles’s Law.
Charles’s Law states that at constant pressure, the volume of a gas is directly proportional to its temperature (V1/T1 = V2/T2).
What is Avogadro’s Law?
Avogadro’s Law states that at constant temperature and pressure, the volume of a gas is directly proportional to the number of moles (V ∝ n).
State Gay-Lussac’s Law.
Gay-Lussac’s Law states that at constant volume, the pressure of a gas is directly proportional to its temperature (P1/T1 = P2/T2).
What units are commonly used for pressure in gas law calculations?
Atmospheres (atm), millimeters of mercury (mmHg), and Pascals (Pa).
What is the standard temperature and pressure (STP) for gases?
0°C (273 K) and 1 atm pressure.
What does the ‘R’ in the ideal gas law stand for?
‘R’ is the gas constant, which equals 0.0821 atm·L/(mol·K) when using atm, liters, and Kelvin.
What is partial pressure?
The pressure exerted by each individual gas in a mixture.
State Dalton’s Law of Partial Pressures.
Dalton’s Law states that the total pressure of a mixture of gases is the sum of the partial pressures of each gas (P_total = P1 + P2 + P3 …).
What is diffusion?
The process of gas molecules spreading out to fill the available volume.
Define effusion.
Effusion is the process where gas particles escape through a tiny hole into a vacuum.
State Graham’s Law of Effusion.
The rate of effusion of a gas is inversely proportional to the square root of its molar mass (Rate1/Rate2 = √(M2/M1)).
How does the molar volume of an ideal gas at STP compare across gases?
The molar volume is the same for all ideal gases at STP, approximately 22.4 L.
Define the term ‘ideal gas.’
An ideal gas is a hypothetical gas that perfectly follows the gas laws under all conditions.
What assumptions are made about ideal gases?
Ideal gases are assumed to have no intermolecular forces and occupy no volume.
What is the kinetic molecular theory?
A theory that describes gas behavior in terms of particle motion, collision, and kinetic energy.
What is the relationship between kinetic energy and temperature in gases?
The average kinetic energy of gas particles is directly proportional to the absolute temperature.
What is meant by ‘real gases’?
Real gases deviate from ideal gas behavior due to intermolecular forces and molecular volume.
Under what conditions do gases deviate most from ideal behavior?
At low temperatures and high pressures.
What is the Van der Waals equation?
An equation that modifies the ideal gas law to account for intermolecular forces and molecular volume.
Why is the ideal gas law considered an approximation?
It assumes gases have no interactions and particles occupy no space, which isn’t true for real gases.
What is meant by the compressibility of a gas?
Compressibility measures how much the volume of a gas decreases under pressure.
What is molar mass and how is it used in gas law calculations?
Molar mass is the mass of one mole of a substance, used to relate mass to moles in gas calculations.
How can you calculate the density of a gas using the ideal gas law?
Density (d) = (PM) / (RT), where M is the molar mass.
How does temperature affect gas pressure?
An increase in temperature increases the kinetic energy and thus increases the pressure of a gas.
How does molecular weight affect the speed of gas molecules?
Lighter gas molecules move faster than heavier ones at the same temperature.
Why do gases have low densities?
The particles are widely spaced, occupying a large volume relative to their mass.
Explain why gas pressure is caused.
Pressure is caused by collisions of gas molecules with the walls of their container.
What happens to gas volume if the pressure is doubled while temperature remains constant?
The volume is halved (Boyle’s Law).
How does the addition of gas molecules affect pressure?
Increasing the number of molecules in a fixed volume increases the pressure.
What is meant by an elastic collision in the kinetic molecular theory?
A collision where no kinetic energy is lost.
What is a vacuum?
A space with no particles and therefore no pressure.
Why do gases expand to fill their container?
Gas particles move freely and spread out until they occupy all available space.
How does atmospheric pressure change with altitude?
Atmospheric pressure decreases with higher altitude.
How does a barometer work?
A barometer measures atmospheric pressure by balancing mercury in a column against air pressure.
What is absolute zero?
The theoretical temperature at which all molecular motion stops (0 K or -273.15°C).
What happens to gas particles at absolute zero?
They have minimum possible kinetic energy.
How does increasing temperature affect gas volume?
Volume increases if the pressure remains constant (Charles’s Law).
How can molar volume be used to find moles of gas?
At STP, volume (L) divided by 22.4 L/mol gives moles of gas.
What is the relationship between the speed of gas molecules and temperature?
As temperature increases, the average speed of gas molecules increases.
How does temperature affect the kinetic energy distribution of gas molecules?
Higher temperatures broaden the distribution and increase average kinetic energy.
Describe the Maxwell-Boltzmann distribution curve.
It shows the range of speeds of gas molecules at a given temperature.
What is the most probable speed in a Maxwell-Boltzmann distribution?
The speed at which the greatest number of molecules move.
What is the impact of intermolecular forces on real gas behavior?
Intermolecular attractions reduce the pressure exerted by real gases compared to ideal gases.
Explain how a gas exerts pressure on the walls of its container.
Gas particles collide with the container walls, transferring momentum and creating pressure.
In terms of kinetic energy, why does a gas expand when heated?
Increased kinetic energy leads to faster-moving particles that spread apart, expanding the volume.
How can the ideal gas law be used to calculate molar mass?
Molar mass (M) = (dRT) / P, where d is the density of the gas.
How does the real gas equation adjust for the volume of gas particles?
The Van der Waals equation includes a term for particle volume (b).
What happens to the ideal gas behavior at very low temperatures?
Ideal gas behavior deviates as particles slow and attractive forces become significant.
