Question

How many moles are in 2.35 x 10^21 Ba atoms

Answer 1

There are 0.00390 moles of Barium in 2.35 × 10²¹ atoms of Ba.

General Formulas and Concepts:
Stoichiometry

• Mole ratio
• Avogadro's Number: 6.023 × 10²³ atoms/moles/molecules/formula units/etc.
• Dimensional analysis

Step-by-step explanation:

Step 1: Define

Identify.

2.35 × 10²¹ atoms Ba

Step 2: Convert

1. [Dimensional Analysis] Set up:
   `\displaystyle 2.35 \cdot 10^(21) \ \text{atoms Ba} \bigg( \frac{1 \ \text{mol Ba}}{6.022 \cdot 10^(23) \ \text{atoms Ba}} \bigg)`
2. [Dimensional Analysis] Evaluate:
   `\displaystyle \displaystyle 2.35 \cdot 10^(21) \ \text{atoms Ba} \bigg( \frac{1 \ \text{mol Ba}}{6.022 \cdot 10^(23) \ \text{atoms Ba}} \bigg) = 0.003902`
3. [Sig Figs] Round:
   `\displaystyle \displaystyle 2.35 \cdot 10^(21) \ \text{atoms Ba} \bigg( \frac{1 \ \text{mol Ba}}{6.022 \cdot 10^(23) \ \text{atoms Ba}} \bigg) \approx 0.00390`

Topic: AP Chemistry

Unit: Stoichiometry