The boiling point of water (100°C) is anomalously HIGH compared to H₂S (−60°C), H₂Se (−41°C), H₂Te (−2°C). This is due to:
A.
Water molecules have higher kinetic energy at room temperature
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
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
8.
THERMAL ENERGY is defined as:
A.
The potential energy stored between molecules at equilibrium distance
B.
The energy required to break all intermolecular forces in a substance
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
D.
The heat absorbed during melting of a solid at its melting point
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
9.
The physical state of a substance is determined by:
A.
The balance between intermolecular forces (which tend to hold molecules together) and thermal energy (which tends to separate molecules by random motion)
A. The balance between intermolecular forces (which tend to hold molecules together) and thermal energy (which tends to separate molecules by random motion)
10.
BOYLE'S LAW (1662) states that at constant temperature, the pressure of a fixed amount of gas is:
A.
Directly proportional to the square of its volume: P ∝ V²
B.
Directly proportional to its volume: P ∝ V at constant T
C.
Independent of its volume — pressure is only temperature-dependent
D.
Inversely proportional to its volume: P ∝ 1/V at constant T and n, i.e., PV = constant (k)
