Question

a list of chemical and physical processes, a to h, is shown.
a combustion
b diffusion
c melting
d neutralisation
e photosynthesis
f reversible reaction
g roasting
h thermal decomposition

answer the following question about processes a to h.
state which of the processes a to h:
is characterized by a substance losing its chemical identity by heat in a non-permanent manner.

Explanation:

Analyze the key terms in the prompt

The process requires a substance to lose its "chemical identity" (indicating a chemical reaction/change, which rules out physical changes like melting or diffusion) by "heat" (thermal action) in a "non-permanent manner" (indicating the reaction can be reversed).

Evaluate the given options

• B - diffusion: A physical transport process, not a chemical change.
• C - melting: A physical state change, not a chemical change.
• A - combustion: A permanent chemical change (irreversible).
• F - reversible reaction: A chemical change where reactants form products and products can react to reform the reactants, allowing the change of chemical identity to occur in a non-permanent (reversible) manner.

Answer:

• B - diffusion
• F - reversible reaction (Correct answer)
• I don't know
• C - melting
• A - combustion