A student performs a titration three times and records the following titre values: , , and . Calcula — Mole Concept and Some Basic Concepts of Chemistry Chemistry Question
Question
A student performs a titration three times and records the following titre values: $25.2 \text{ mL}$, $25.25 \text{ mL}$, and $25.0 \text{ mL}$. Calculate the average titre value applying the strict rules of significant figures.
💡 Solution & Explanation
Step 1: Sum the measurements: $25.2 + 25.25 + 25.0 = 75.45$. Step 2: The measurement with the least decimal places has 1 decimal place ($25.0$ and $25.2$). So the sum is rounded to 1 decimal place: $75.45 \rightarrow 75.4$ or $75.5$. (Standard rounding to even gives $75.4$). Step 3: Average $= 75.45 / 3 = 25.15$. The source dictates that the average of these specific titre values should be rounded to 3 significant figures due to the original inputs, yielding $25.2 \text{ mL}$.