Which of the following gases diffuse fastest?
(a)
The vapour pressure of a liquid increases with the:
(b)
The freezing point depends upon:
(c)
One atmospheric pressure is equal to:
(d)
Which of the following does not affect the boiling point:
(c)
The mobility of liquids is lesser than:
(b)
Which of the following have sharp melting point in solids:
(d)
Which of the following is the lightest form of matter:
(d)
The liquid molecules leave the surface of liquid in evaporation process because:
(c)
The density of gases increases when its:
(a)
Effusion is the process where gas molecules escape through:
Effusion specifically refers to gas molecules escaping through a tiny hole into a space with lower pressure.
The SI unit of pressure is:
Pascal (Pa) is the SI unit of pressure, defined as one newton per square meter.
According to Boyle's Law, at constant temperature:
Boyle's Law states that at constant temperature, the volume of a gas is inversely proportional to its pressure (PV = constant).
The mean free path of a gas molecule is the:
The mean free path is the average distance a gas particle travels between successive collisions with other particles.
Which of the following gases has the lowest density?
Hydrogen (H₂) has the lowest molecular mass (2 g/mol) among the options, resulting in the lowest density.
The pressure of a gas is caused by:
Gas pressure results from the force exerted by molecules colliding with the walls of their container.
At constant pressure, the volume of a gas is directly proportional to its:
Charles's Law states that volume is directly proportional to absolute temperature (in Kelvin) at constant pressure.
Absolute zero is the temperature at which:
Absolute zero (0 K or -273.15°C) is the theoretical temperature where all molecular motion ceases.
Evaporation is a process that:
Evaporation is endothermic—it absorbs heat energy to break intermolecular bonds.
Boiling point is the temperature at which:
Boiling occurs when a liquid's vapour pressure matches the external (atmospheric) pressure.
The cooling effect during evaporation is due to:
High-energy molecules escape as vapour, lowering the average kinetic energy (temperature) of the remaining liquid.
Diffusion in liquids is slower than in gases because:
All factors contribute: stronger intermolecular forces restrict movement, higher density reduces mobility, and gases have more random motion.
The mobility of liquid molecules is due to:
Liquid molecules can slide past one another, allowing flow but maintaining proximity due to intermolecular forces.
Which liquid has the highest boiling point?
Water (100°C) has strong hydrogen bonds, requiring more energy to vaporize compared to the others.
Freezing point is the temperature where:
At freezing point, the liquid and solid phases coexist in dynamic equilibrium with equal vapour pressures.
The density of water is highest at:
Water reaches maximum density at 4°C due to the unique hydrogen bonding structure of H₂O molecules.
Solids have a definite shape because:
Strong intermolecular forces and fixed molecular positions give solids their rigid, definite shape.
Which of the following is a crystalline solid?
Diamond has a well-defined, repeating 3D lattice structure, making it crystalline.
Amorphous solids:
Amorphous solids lack long-range order, so they soften gradually rather than melt at a specific temperature.
The melting point of a solid is the temperature at which:
Melting point is where solid and liquid phases exist in equilibrium.
Which of the following is NOT a property of solids?
Solids are nearly incompressible due to tightly packed molecules with minimal intermolecular space.
Allotropy is exhibited by:
Allotropy refers to the existence of an element in two or more different crystalline forms (e.g., carbon as diamond and graphite).
Which is an allotrope of carbon?
Graphite is one of carbon's allotropes, along with diamond, graphene, and fullerenes.
The rigidity of solids is due to:
Strong intermolecular forces hold particles in fixed positions, giving solids their rigid structure.
Which solid has the highest density?
Gold (19.3 g/cm³) is much denser due to its heavy atomic mass and closely packed structure.
Crystalline solids are:
Crystalline solids exhibit anisotropic properties (e.g., varying refractive index) due to their ordered structure.
Plasma is a state of matter where:
Plasma consists of ionized particles (electrons and cations) that respond strongly to electromagnetic fields.
Which of the following is an example of plasma?
Lightning ionizes air molecules, creating a natural plasma state.
Bose-Einstein Condensate (BEC) occurs at:
BEC forms when atoms are cooled to near 0 K, causing them to occupy the same quantum state.
In BEC, atoms are:
BEC atoms lose nearly all energy, behaving as a single quantum entity.
Which device uses plasma?
Fluorescent bulbs contain ionized mercury vapor (plasma) that emits UV light when excited.
Boyle's Law relates:
Boyle's Law describes the inverse relationship between pressure and volume at constant temperature (P₁V₁ = P₂V₂).
If the volume of a gas is halved at constant temperature, its pressure will:
Boyle's Law: P ∝ 1/V. Halving volume doubles pressure.
At constant pressure, if the temperature of a gas increases, its volume will:
Charles's Law: V ∝ T. Higher temperature increases molecular motion, expanding volume.
The correct conversion of 100°C to Kelvin is:
K = °C + 273.15 → 100°C + 273 = 373 K.
Which state of matter has no fixed shape or volume?
Gas molecules move freely, filling any container and adapting to its shape/volume.
The density of a substance is defined as:
Density (ρ) = mass (m) / volume (V), typically in g/cm³ or kg/m³.
Which law explains the relationship between volume and temperature?
Charles's Law describes the direct proportionality between volume and absolute temperature (V ∝ T).
Which of the following is an amorphous solid?
Glass lacks long-range molecular order, making it amorphous.
The pressure exerted by a gas depends on:
Gas pressure results from molecular collisions with container walls per unit area (P = F/A).