Question

How many moles are in 3.45g of KCI ?

Answer 1

Answer:

0.0463 mol KCl

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

• Reading a Periodic Table
• Using Dimensional Analysis

Explanation:

Step 1: Define

3.45 g KCl

Step 2: Identify Conversions

Molar Mass of K - 39.10 g/mol

Molar Mass of Cl - 35.45 g/mol

Molar Mass of KCl - 39.10 + 35.45 = 74.55 g/mol

Step 3: Convert

1. Set up:                              $\displaystyle 3.45 \ g \ KCl(\frac{1 \ mol \ KCl}{74.55 \ g \ KCl})$
2. Multiply/Divide:                $\displaystyle 0.046278 \ mol \ KCl$

Step 4: Check

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

0.046278 mol KCl ≈ 0.0463 mol KCl