The question asks why water's boiling point is unusually high compared to other hydrides of Group 16 elements (H₂S, H₂Se, H₂Te). We need to consider the intermolecular forces present in these compounds.
Correct Option: B) Strong intermolecular HYDROGEN BONDING in water (O-H···O) — each water molecule can form up to 4 H-bonds with neighbours, requiring much more energy to vaporise. This option correctly identifies hydrogen bonding as the primary reason for water's anomalously high boiling point. The extensive network of hydrogen bonds requires a large amount of thermal energy to overcome, leading to a high boiling point.
The question asks for the definition of thermal energy. We need to identify the option that accurately describes thermal energy and its relationship with temperature.
C) The energy of a body arising from the motion (translational, rotational, vibrational) of its atoms or molecules — it is directly proportional to the absolute temperature. This is the precise definition of thermal energy. It is the sum of the kinetic energies of all the particles within a substance, and this kinetic energy is directly linked to the absolute temperature.
The physical state of a substance (solid, liquid, or gas) is determined by the interplay of two opposing factors: forces that try to hold molecules together and energy that tries to separate them. We need to identify the option that best describes this balance.
A) The balance between intermolecular forces (which tend to hold molecules together) and thermal energy (which tends to separate molecules by random motion) is the correct explanation. This option accurately describes the dynamic equilibrium that dictates whether a substance exists as a solid, liquid, or gas.
The question asks about Boyle's Law, a fundamental gas law. We need to recall the relationship between pressure and volume for a fixed amount of gas at a constant temperature as defined by Boyle's Law.
Correct Option: D) Inversely proportional to its volume: \(P \propto 1/V\) at constant T and n, i.e., \(PV = \text{constant (k)}\). This option accurately states Boyle's Law, which describes that for a fixed amount of gas at constant temperature, pressure and volume are inversely related.
This problem involves the relationship between pressure and volume of a gas at constant temperature, which is described by Boyle's Law. Boyle's Law states that for a fixed mass of gas at constant temperature, the pressure is inversely proportional to its volume.
Correct Option: D) The calculation \(P_2 = P_1V_1/V_2 = (1 \text{ bar} \times 500 \text{ dm}^3)/200 \text{ dm}^3 = 2.5 \text{ bar}\) correctly applies Boyle's Law and yields the correct final pressure.
The question asks about Charles' Law, a fundamental gas law. We need to recall the statement of Charles' Law and its mathematical representation.
B) Directly proportional to absolute temperature (T in Kelvin): V \(\propto\) T at constant P and n, i.e., V/T = constant — This statement accurately defines Charles' Law. It correctly specifies that volume is directly proportional to the absolute temperature when pressure (P) and the amount of gas (n) are kept constant. The mathematical representation \(V/T = \text{constant}\) is also correct.