Question detail

Calculate the number of moles in 50 grams of water (H2O).

Try the question, check the answer, then read the explanation to understand the curriculum point.

At a glance

MCQ

Type

practice

Style

Topic

Use of amount of substance in relation to masses of pure substances

Question

  1. A. 2.78 mol
  2. B. 2.78 moles
  3. C. 2.78
  4. D. 0.56 mol

Answer

2.78 mol

Explanation

The relative formula mass of water (H2O) is 18 g/mol. Using the formula moles = mass / Mr, we find that 50 g / 18 g/mol = 2.78 mol.

Common mistake

Common Mistake in Substituting Values

Students often forget to include the correct units when substituting numerical values into algebraic equations.

Always ensure to write the units next to each numerical value during substitution to maintain clarity and accuracy.

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