States of Matter and Separation Techniques

Alcohol and water are miscible liquids with different boiling points. Fractional distillation is the standard laboratory method used to separate such mixtures.

Pure substances have a fixed composition and consistent physical and chemical properties throughout any given sample.

Diffusion is the movement of particles from a region of higher concentration to lower concentration. Because gas particles have high kinetic energy and large intermolecular spaces, they diffuse much faster than liquids or solids.

Iron is a magnetic material, while sulfur is non-magnetic. A magnet can be used to attract the iron powder, leaving the sulfur behind.

In solids, particles are tightly packed with strong intermolecular forces (the question says 'intra molecular' but means intermolecular). These forces hold particles in fixed positions, giving solids their definite shape and volume.

Evaporation is the process used to recover dissolved solids from a liquid solution. Seawater is left in shallow pits where the sun evaporates the water, leaving salt behind.

Crystallization is the process of forming solid crystals from a solution, which is the standard method for purifying solid substances like table salt.

The human body is composed of approximately 70 percent water by mass, which is a standard biological fact.

Solids are characterized by having a definite shape and a definite volume because their particles are fixed in a rigid structure.

The four fundamental states of matter are solid, liquid, gas, and plasma. Plasma is considered the fourth state.

Solid carbon dioxide is known as dry ice because it undergoes sublimation directly from a solid to a gas at atmospheric pressure, leaving no liquid behind.

A suspension of chalk and water contains insoluble particles. Filtration is the most effective way to separate these solid particles from the liquid.

As temperature decreases, particles lose kinetic energy and move closer together, making the solid state the most stable form of matter at low temperatures.

The melting point of ice is 0 degrees Celsius, which is equivalent to 273.15 Kelvin (often rounded to 273 K). Therefore, both B and C are correct.

The boiling point of ethanol (common alcohol) is approximately 78 degrees Celsius at standard atmospheric pressure.

Sublimation is the phase transition where a substance changes directly from a solid to a gas without passing through the liquid phase.

Evaporation is the surface phenomenon where liquid molecules gain enough energy to escape into the vapor phase at temperatures below the boiling point.

Relative humidity is a measure of how much water vapor is in the air compared to the maximum it can hold. At 100 percent humidity, the air is saturated, meaning no more water can evaporate into it.

Transpiration is the biological process by which plants release water vapor from their leaves into the atmosphere.

Crystallization is the standard laboratory process used to separate a solid solute from a solution by cooling or evaporating the solvent. Sublimation is for solids that transition directly to gas, and filtration separates insoluble solids from liquids.

Distilled water is produced through the process of distillation, which involves boiling water into steam and then condensing it back into a liquid to remove impurities. Filtration and evaporation do not remove dissolved impurities as effectively as distillation.

Evaporation rate depends on the strength of intermolecular forces and boiling points. Water has strong hydrogen bonding and a higher boiling point compared to alcohol or ether, making it evaporate the slowest among the choices.

Evaporation is an endothermic process because it requires the input of energy (latent heat of vaporization) to overcome the intermolecular forces holding the liquid molecules together. This energy is absorbed from the surroundings, causing a cooling effect.