During the phase transition of a substance from solid to liquid, which of the following changes does NOT occur?
Show answer Hide answer
Answer: B. K.E of the molecules decreases
Explanation
During the phase transition from solid to liquid, thermal energy is absorbed to weaken intermolecular forces. This added thermal energy increases molecular movement and structural disorder within the liquid phase. Because thermal energy is absorbed and converted to motion, molecular kinetic energy actually increases rather than decreases. Melting is an endothermic phase change where a solid transforms into a liquid at its melting point. Intermolecular forces hold solid crystal lattices together, requiring heat energy to overcome. Kinetic energy of molecules is directly proportional to the temperature of the system.
Industrial metal casting relies on understanding phase transitions to melt and mold solid metals safely. Calorimetry experiments measure heat of fusion to determine the energy required for melting substances. Phase changes are fundamental concepts in thermodynamics and physical chemistry. Molecules become more disordered during melting because the rigid crystal lattice breaks down. Intermolecular forces become weaker as molecules move apart during the solid-to-liquid transition. Molecules move more frequently because increased kinetic energy breaks fixed positions.
Related questions
Q1. Chemically, animal and vegetable fats are classified as___________________?
Show answer Hide answer
Answer: C. Triesters formed from glycerol and fatty acids
Animal and vegetable fats consist of a glycerol molecule esterified with three long-chain fatty acids. This chemical structure classifies them strictly as triesters, commonly referred to as triglycerides. Ester bonds for...
Q2. Which scientists were responsible for the discovery of argon gas_______?
Show answer Hide answer
Answer: B. Ramsay
Sir William Ramsay collaborated with Lord Rayleigh to discover and isolate argon gas. They removed oxygen and nitrogen from atmospheric air samples to find a residual gas. Spectroscopic analysis of this unreactive residu...
Q3. At what specific numeric value on the pH scale is a solution considered neutral?
Show answer Hide answer
Answer: C. 7
On the standard pH scale, a neutral solution has an equal balance of hydronium and hydroxide ions. At twenty-five degrees Celsius, the self-ionization constant of water results in a neutral pH value. This exact midpoint...
Q4. Which chemical theory is supported by defining a base as any substance capable of accepting a proton (H+)___________________?
Show answer Hide answer
Answer: A. Lowrys
The Lowry-Bronsted theory defines acids as proton donors and bases as proton acceptors in reactions. This definition broadened acid-base chemistry beyond aqueous solutions to include various proton transfers. Consequentl...
Q5. Do elements with higher atomic numbers generate X-rays with higher or lower energy/penetration__________________?
Show answer Hide answer
Answer: A. Shorter wavelength
Moseley law establishes that higher atomic numbers produce X-rays with higher frequencies. Higher X-ray frequencies correspond directly to shorter electromagnetic wavelengths. Increased nuclear charge pulls inner-shell e...
Q6. Where within an atom is the vast majority of its atomic mass localized__________?
Show answer Hide answer
Answer: C. Nucleus
An atom consists of a central nucleus surrounded by orbiting electrons in various energy levels. Protons and neutrons reside inside this central nucleus, possessing relatively large particle masses. Electrons have neglig...