Question

How many molecules are in 0.55 moles of Cu(NO3)2?

Answer 1

Answer:

3.3 × 10²³ molecules Cu(NO₃)₂

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

0.55 mol Cu(NO₃)₂

Step 2: Identify Conversions

Avogadro's Number

Step 3: Convert

1. [DA] Set up:                                                                                                     $\displaystyle 0.55 \ mol \ Cu(NO_3)_2(\frac{6.022 \cdot 10^{23} \ molecules \ Cu(NO_3)_2}{1 \ mol \ Cu(NO_3)_2})$
2. [DA] Multiply/Divide [Cancel out units]:                                                         $\displaystyle 3.3121 \cdot 10^{23} \ molecules \ Cu(NO_3)_2$

Step 4: Check

Follow sig fig rules and round. We are given 2 sig figs.

3.3121 × 10²³ molecules Cu(NO₃)₂ ≈ 3.3 × 10²³ molecules Cu(NO₃)₂