Question

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

Answer 1

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.

Step-by-step 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((1 \ mol \ K)/(39.10 \ g \ K) )((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