COMEDK · Chemistry · 1. Some Basic Concepts of Chemistry
A signature, written in carbon pencil weighs \(1 \mathrm{mg}\). What is the number of carbon atoms present in the signature?
- A \(5.02 \times 10^{23}\)
- B \(5.02 \times 10^{20}\)
- C \(6.02 \times 10^{20}\)
- D \(0.502 \times 10^{20}\)
Answer & Solution
Correct Answer
(D) \(0.502 \times 10^{20}\)
Step-by-step Solution
Detailed explanation
Number of carbon atoms \[ \begin{aligned} &=\frac{\text { mass }}{\text { molar mass }} \times 6.023 \times 10^{23} \\ &=\frac{10^{-3}}{12} \times 6.023 \times 10^{23} \\ &=5.02 \times 10^{19}=0.502 \times 10^{20} \end{aligned} \]
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