Question

How many atoms are present in a sample of Potassium (K) weighing 33.49g?

Answer 1

Answer:

5.158 × 10²³ atoms K

General Formulas and Concepts:

Chemistry - Atomic Structure

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

Explanation:

Step 1: Define

33.49 g K

Step 2: Identify Conversions

Avogadro's Number

Molar Mass of K - 39.10 g/mol

Step 3: Convert

$33.49 \ g \ K(\frac{1 \ mol \ K}{39.10 \ g \ K} )(\frac{6.022 \cdot 10^{23} \ atoms \ K}{1 \ mol \ K} )$ = 5.15797 × 10²³ atoms K

Step 4: Check

We are given 4 sig figs. Follow sig figs and round.

5.15797 × 10²³ atoms K ≈ 5.158 × 10²³ atoms K