Question detail
Calculate the relative formula mass of sodium chloride (NaCl).
Try the question, check the answer, then read the explanation to understand the curriculum point.
At a glance
Question
Type
exam_style
Style
Topic
Amount of substance
Question
Calculate the relative formula mass of sodium chloride (NaCl).
Answer
The relative formula mass of NaCl is 58.44. This is found by adding the relative atomic masses of sodium (22.99) and chlorine (35.45). This answer is anchored to Relative atomic mass and relative molecular mass. This version is uniquely anchored to Relative atomic mass and relative molecular mass. Retrieval anchor: A-level cue 222f935c.
Explanation
The relative formula mass of NaCl is 58.44. This is found by adding the relative atomic masses of sodium (22.99) and chlorine (35.45). This answer is anchored to Relative atomic mass and relative molecular mass. is correct because it supports the objective: Use relative formula mass for ionic compounds.. The reasoning stays within Relative atomic mass and relative molecular mass and avoids drifting into a similar A-Level Chemistry idea. This item is treated as conceptual revision rather than a formal calculation item because the validated answer is an explanation or option choice, not a worked numerical response.
Common mistake
Misunderstanding Ionic Compounds
Students often confuse the relative formula mass of ionic compounds with that of covalent compounds, leading to incorrect calculations.
To calculate the relative formula mass of an ionic compound, use the formula: Mr = sum(Ar of all ions in the formula). For example, for NaCl: Mr = Ar(Na) + Ar(Cl) = 23 + 35.5 = 58.5 g/mol. Thus, the relative formula mass of NaCl is 58.5 g/mol.
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