객관식
Aqua regia is a mixture of which of the following substances?
131
views
1. Intro to General Chemistry
Chemical Properties
객관식
Which of the following statements correctly describes the chemical property involved in the evaporation of methanol at 25.0 °C: CH3OH(l) → CH3OH(g)?
A
Evaporation of methanol is a physical change because no new substances are formed.
B
Evaporation of methanol is a chemical change because the chemical composition of methanol changes.
C
Evaporation of methanol involves breaking covalent bonds within the CH3OH molecule.
D
Evaporation of methanol results in the formation of methanal (CH2O) as a product.
검증된 단계별 안내1
Understand the difference between physical and chemical changes: A physical change affects the state or appearance of a substance without altering its chemical composition, while a chemical change results in the formation of new substances with different chemical properties.
Analyze the process of evaporation: Evaporation is the transition of a substance from the liquid phase to the gas phase, which involves overcoming intermolecular forces but does not break covalent bonds within the molecules themselves.
Apply this to methanol (CH3OH): When methanol evaporates, the molecules move from liquid to gas, but the chemical formula CH3OH remains unchanged, indicating no new substances are formed.
Evaluate the given statements: Since evaporation does not change the chemical composition or create new substances, it is classified as a physical change, not a chemical change.
Conclude that evaporation of methanol does not involve breaking covalent bonds or forming methanal (CH2O), so the correct description is that evaporation is a physical change because no new substances are formed.
관련 영상
관련 실천
