Question

How many moles of Ca are in 3.75 x 10^25 atoms of Ca?

Answer 1

Answer:

62.3 mol Ca

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

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

Stoichiometry

• Using Dimensional Analysis

Explanation:

Step 1: Define

3.75 × 10²⁵ atoms Ca

Step 2: Identify Conversions

Avogadro's Number

Step 3: Convert

1. Set up:                              $\displaystyle 3.75 \cdot 10^{25} \ atoms \ Ca(\frac{1 \ mol \ Ca}{6.022 \cdot 10^{23} \ atoms \ Ca})$
2. Multiply/Divide:                $\displaystyle 62.2717 \ mol \ Ca$

Step 4: Check

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

62.2717 mol Ca ≈ 62.3 mol Ca