Lesson: Chapter 7 — Quantification of Elements and Compounds

7.1. Relative atomic mass 4 of 12 Reset answers

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Question 4

The mass of a carbon-12 atom is 1.99 × 10^-23 g. What is the value of the atomic mass unit?

A 1.66 × 10^-23 g B 2.39 × 10^-22 g C 1.66 × 10^-24 g D 1.99 × 10^-23 g

The right answer is the one marked above.

1.66 × 10^-24 g. It comes from (1.99 × 10^-23 g) ÷ 12.

1.99 × 10^-23 g is the whole mass of the carbon atom — the division by 12 has been forgotten. Multiplying by 12 instead of dividing gives 2.39 × 10^-22.

Answer the question to continue.