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How many entities are present in exactly one mole of any substance (the value of Avogadro's number)?
A$3.011 \times 10^{23}$
B$6.023 \times 10^{22}$
C$6.023 \times 10^{23}$
D$12.046 \times 10^{23}$
Answer & Solution
Correct answer: C. $6.023 \times 10^{23}$
1. One mole is defined as the number of atoms in exactly 12 g of carbon-12.
2. This experimentally determined number is Avogadro's number $N_A$.
3. Its value is $6.023 \times 10^{23}$ entities per mole.
_Source: Samacheer Kalvi (TN SCERT) Class 10 Science, Unit 7 Atoms and Molecules "Mole Concept", p.103_
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