How many atoms are in 57.5 liters of xenon gas at STP

1.55 × 10²⁴ atoms Xe

General Formulas and Concepts:

Atomic Structure

Reading a Periodic TableMolesSTP (Standard Conditions for Temperature and Pressure) = 22.4 L per mole at 1 atm, 273 K Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.

Stoichiometry

Using Dimensional Analysis

Explanation:

Step 1: Define

[Given] 57.5 L Xe at STP

[Solve] atoms Xe

Step 2: Identify Conversions

[STP] 22.4 L = 1 mol

Avogadro's Number

Step 3: Convert

[DA] Set up:                                                                                                       [DA] Divide/Multiply [Cancel out units]:                                                          

Step 4: Check

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

1.54583 × 10²⁴ atoms Xe ≈ 1.55 × 10²⁴ atoms Xe