Question

How many moles of lead, Pb, are in 1.50 x 10^12 atoms of lead?

Answer 1

Answer:

2.49 × 10⁻¹² moles Pb

General Formulas and Concepts:

Math

Pre-Algebra

Order of Operations: BPEMDAS

1. Brackets
2. Parenthesis
3. Exponents
4. Multiplication
5. Division
6. Addition
7. Subtraction

• Left to Right

Chemistry

Atomic Structure

• Using Dimensional Analysis
• Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.

Explanation:

Step 1: Define

1.50 × 10¹² atoms Pb

Step 2: Identify Conversions

Avogadro's Number

Step 3: Convert

1. Set up:                                         $\displaystyle 1.50 \cdot 10^{12} \ atoms \ Pb(\frac{1 \ mol \ Pb}{6.022 \cdot 10^{23} \ atoms \ Pb})$
2. Multiply:                                                                                                           $\displaystyle 2.49087 \cdot 10^{-12} \ moles \ Pb$

Step 4: Check

Follow sig fig rules and round. We are given 3 sig figs.

2.49087 × 10⁻¹² moles Pb ≈ 2.49 × 10⁻¹² moles Pb