How many moles are in 7.2x10^15 atoms of Pb?​

1.2 × 10⁻⁸ mol Pb

General Formulas and Concepts:

Math

Pre-Algebra

Order of Operations: BPEMDAS

Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to Right

Chemistry

Atomic Structure

Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.

Stoichiometry

Using Dimensional AnalysisExplanation:

Step 1: Define

[Given] 7.2 × 10¹⁵ atoms Pb

Step 2: Identify Conversions

Avogadro's Number

Step 3: Convert

[DA] Set up:                                                                                                     [DA] Multiply/Divide [Cancel out units]:                                                            

Step 4: Check

Follow sig fig rules and round. We are given 2 sig figs.

1.19562 × 10⁻⁸ mol Pb ≈ 1.2 × 10⁻⁸ mol Pb

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