Question

How many moles are in 8.63 x 103 atoms of Li?

Answer 1

Answer:

1.43 × 10⁻²⁰ mol Li

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

8.63 × 10³ atoms Li

Step 2: Identify Conversions

Avogadro's Number

Step 3: Convert

1. Set up:                              $\displaystyle 8.63 \cdot 10^3 \ atoms \ Li(\frac{1 \ mol \ Li}{6.022 \cdot 10^{23} \ atoms \ Li})$
2. Multiply/Divide:                $\displaystyle 1.43355 \cdot 10^{-20} \ moles \ Li$

Step 4: Check

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

1.43355 × 10⁻²⁰ mol Li ≈ 1.43 × 10⁻²⁰ mol Li