States Of Matter : Gases And Liquids (VSAQs)

Chemistry-1 | 4. States of Matter: Gases and Liquids – VSAQs:
Welcome to VSAQs in Chapter 4: States of Matter: Gases and Liquids. This page includes the important FAQs for Very Short Answer Questions. Answers are provided in simple English and follow the exam format. This approach helps in focusing on essential points and achieving top marks in your final exams.

VSAQ-1 : State Graham’s law of diffusion.

Graham’s Law of Diffusion

Statement: Graham’s law of diffusion states that the rate at which a gas diffuses (or effuses) is inversely proportional to the square root of its molar mass.

Mathematical Representation:

$$\text{Rate}_1 / \text{Rate}_2 = \sqrt{\frac{\text{Molar Mass}_2}{\text{Molar Mass}_1}}$$

This law helps predict how gases with different molar masses will diffuse or effuse, with lighter gases exhibiting faster rates under the same conditions.

VSAQ-2 : State Dalton’s law of partial pressures.

Dalton’s Law of Partial Pressures

Statement: Dalton’s law of partial pressures states that the total pressure in a gas mixture is equal to the sum of the partial pressures of each gas component in the mixture.

Mathematical Representation:

$$P_{\text{Total}} = P_1 + P_2 + P_3 + \ldots$$

Here, P_Total represents the total pressure, and P1, P2, P3, and so on, represent the partial pressures of individual gases in the mixture. This law is essential for understanding and calculating gas pressures in gas mixtures.

VSAQ-3 : What is surface tension?

Surface Tension

  1. Definition: Surface tension is the force per unit length acting on the surface of a liquid, perpendicular to any line on that surface.
  2. Significance: It causes liquids to form droplets and allows objects to float on water, driven by cohesive forces between liquid molecules. Surface tension is crucial in capillary action, water droplet behavior, and soap bubble formation, with applications in chemistry, physics, and biology. Measured in Newtons per meter (N/m) in SI units.

VSAQ-4 : What is Boltzman’s Constant? Give its value.

Boltzmann’s Constant

  1. Definition: Boltzmann’s constant (symbol: k) relates the average kinetic energy of particles in a gas with the temperature of the gas. It’s essentially the gas constant (R) divided by Avogadro’s number (N), making it the gas constant per molecule.
  2. Value: Boltzmann’s constant is approximately 1.38 x 10^(-23) Joules per Kelvin (J/K).
  3. Significance: It’s a fundamental constant in physics and is used in various equations, particularly in statistical mechanics and thermodynamics, to relate macroscopic properties of gases to the behavior of individual particles at the microscopic level.
  4. Units: The SI units for Boltzmann’s constant are Joules per Kelvin (J/K).

VSAQ-5 : Which gas diffuses faster among N2,O2,CH4 gases? Why?

Among the gases N₂, O₂, and CH₄, CH₄ (methane) diffuses fastest. This is because the rate of diffusion is inversely proportional to the square root of the molar mass, and methane has the lowest molar mass among the three gases. According to Graham’s law of diffusion, lighter gases diffuse faster under identical conditions, making methane the fastest diffusing gas in this case.

VSAQ-6 : How many times methane diffuses faster than Sulphurdioxide?

Methane (CH₄) diffuses approximately two times faster than Sulphur dioxide (SO₂). This difference in diffusion rates is due to the significant difference in their molar masses, as dictated by Graham’s law of diffusion, which states that the rate of diffusion is inversely proportional to the square root of the molar mass. Methane has a lower molar mass compared to Sulphur dioxide, resulting in its faster diffusion.

VSAQ-7 : Find kinetic energy of 5 moles of an ideal gas in calories at 27°C

Kinetic Energy of 5 Moles of Gas at 27°C

Calculation: Using the formula for kinetic energy, with 5 moles of gas at 27°C:

KE ≈ 4462 calories