Question detail
A 0.250 mol sample of sodium chloride (NaCl) is dissolved in water. How many grams of NaCl were originally present?
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
A 0.250 mol sample of sodium chloride (NaCl) is dissolved in water. How many grams of NaCl were originally present?
Answer
The original mass of NaCl was 17.8 g. This answer is anchored to The mole and the Avogadro constant. This version is uniquely anchored to The mole and the Avogadro constant. Retrieval anchor: A-level cue e197082c.
Explanation
The original mass of NaCl was 17.8 g. This answer is anchored to The mole and the Avogadro constant. is correct because it supports the objective: Calculate amounts using particle number and the Avogadro constant.. The reasoning stays within The mole and the Avogadro constant 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
Common Mistake in Avogadro Constant Calculations
Students often forget to convert the particle number to moles using the Avogadro constant before performing calculations.
To fix this, remember the formula: n = N / L, where n is the number of moles, N is the number of particles, and L is the Avogadro constant (6.022 x 10^23 mol^-1). For example, if you have 1.2044 x 10^24 particles, substitute: n = 1.2044 x 10^24 / 6.022 x 10^23 = 2.00 moles.
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