Lesson eLearning

A hospital uses chlorhexidine solution 0.5% for hand washing. If a patient uses 10 mL per hand wash, how many grams of chlorhexidine are used per wash?

medium 2 marks Class 8 · Science · Microorganisms - Friend and Foe
Answer
0.05 g

The correct answer is 0.05 g — 10 mL contains (0.5/100)×10 = 0.05 g of chlorhexidine.

Step-by-step solution

  1. 0.5% solution means 0.5 g of chlorhexidine per 100 mL.
  2. 10 mL contains (0.5/100)×10 = 0.05 g of chlorhexidine.
Common mistake: Treating 0.5% as 0.5 g per 1 L instead of per 100 mL.

Concept tested: Antiseptic concentration calculations

Published · How this solution was prepared and checked

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