States of Matter

Ans : 1

A vacuum is an empty space with very low pressure - essentially absence of matter. It's the absence of gas, liquid, or solid particles.

Hoar frost forms when air temperature is below the frost point, causing water vapor to deposit directly as ice crystals on surfaces without passing through a liquid phase. This differs from rime and glaze ice which involve supercooled liquid water freezing on contact.

Impact ice forms when supercooled water droplets (liquid water below freezing temperature) strike exposed parts of an aircraft, particularly in the air intake and induction system. The droplets freeze instantly upon contact with the aircraft surface, creating a rough ice accumulation that can disrupt airflow and engine performance. This differs from rime ice (formed through rapid freezing of small droplets) and glaze ice (formed when larger droplets spread before freezing).

Desorption is a phenomenon whereby a substance is released from or through a surface. This occurs in a system being in the state of sorption equilibrium between bulk phase (fluid, i.e. gas or liquid solution) and an adsorbing surface (solid or boundary separating two fluids).

All are applications of colloids.

Emulsion are the colloidal solutions in which both the dispersed phase and the dispersion medium are liquids. A good example of an emulsion is milk in which fat globules are dispersed in water. The size of the emulsified globules is generally of the order of 10^-6 m. Emulsion resembles lyophobic sols in some properties.

A miniemulsion is a special case of emulsion. A miniemulsion is obtained by shearing a mixture comprising two immiscible liquid phases, one surfactant and one co-surfactant. Typical examples are hexadecane or cetyl alcohol.

When ice floats in water and melts, the water level remains the same. This is because the volume of water displaced by the ice equals the volume of water produced when the ice melts. Ice is less dense than liquid water, which is why it floats.

(a branch of science concerned with). Correct word order. All the other options make use of words which makes the sentence incomplete. 

It is correct as by the time water has cooled to 4⁰C., the molecules' energy has dropped enough that they are very near each another. So each H₂O molecule forms more stable hydrogen bonds, with up to four fellow molecules. At 0⁰C, the molecules in ice are held rigidly apart. That means more empty space between molecules, so frozen water occupies more room and is less dense.

It is correct as water molecules are less dense than ice. Water expands on cooling.

This is correct. In a pure chemical compound, elements are always present in a definite proportion by mass. This is known as the law of definite proportions. In this case, if we decompose 100 grams of pure water by passing electricity through it, then we get 11 grams of hydrogen and 89 grams of oxygen, showing that hydrogen and oxygen are combined together in water in the same constant proportion of 1 : 8 by weight.

Water is used in car radiators primarily because of its high specific heat capacity (4200 J/kg°C), meaning it can absorb large amounts of heat for small temperature changes. This makes it excellent for cooling engines. While water is also easily available and has high density, these are not the primary reasons. Low boiling point would actually be a disadvantage.

Rain water is the purest form of natural water because it forms through the process of evaporation and condensation, which naturally removes most impurities. River water contains dissolved minerals and pollutants from the ground it flows over, filtered water still contains some dissolved substances, and mineral water has added minerals for taste.