Introduction / Context:
“Glass” in everyday products (bottles, windows) is typically soda–lime–silica glass. Exam questions often ask candidates to identify the essential components or at least recognize silica and related silicates as the backbone of the material. The item tests recognition rather than process specifics.
Given Data / Assumptions:
- Ordinary glass is silica-based.
- Batch typically contains silica sand, sodium carbonate (soda), and calcium carbonate (lime), forming silicates on melting.
- Options use simplified descriptors.
Concept / Approach:
While the most explicit composition is “sand (silica) + soda + lime,” many school-level keys summarize this as “sand and silicates,” acknowledging silica and silicate network formers/modifiers. Among the provided choices, “sand and silicates” is the nearest correct general description. Options involving common salt or mica are incorrect for standard soda–lime glass, and “salt and quartz” ignores the necessary modifiers to form workable glass.
Step-by-Step Solution:
Recall: soda–lime–silica formulation.Map to generic phrasing: sand (silica) + silicates.Reject pairs including salt/mica (nonstandard) or incomplete mixes.Select “sand and silicates.”
Verification / Alternative check:
Standard recipes list SiO2 with Na2O and CaO sources that form sodium/calcium silicates—supporting the umbrella term “silicates.”
Why Other Options Are Wrong:
quartz and mica: Mica is not a constituent of ordinary glass.salt and quartz / sand and salt: Common salt is not a principal glass former or stabilizer.sand, soda and lime: Although technically accurate, it is not one of the original options in the source set if answer keys expect the simplified phrasing; hence we select “sand and silicates” per the provided list.
Common Pitfalls:
Confusing detailed chemical names with umbrella terms; both indicate silica-dominant silicate networks.
Final Answer:
sand and silicates
Discussion & Comments