Question

Calculate the volume in milliliters of 1.57 M potassium hydroxide that contains 10.3 g of solute.

Answer 1

`V = 0.117 \ L`

General Formulas and Concepts:

Chem

• Reading a Periodic Table
• Writing compounds and polyatomic ions
• Molarity = moles of solute / liters of solution

Step-by-step explanation:

Step 1: Define

1.57 M KOH (potassium hydroxide)

10.3 g KOH

Step 2: Define conversions

Molar Mass of K - 39.10 g/mol

Molar Mass of O - 16.00 g/mol

Molar Mass of H - 1.01 g/mol

Molar Mass of KOH - 39.10 + 16.00 + 1.01 = 56.11 g/mol

Step 3: Convert

`10.3 \ g \ KOH((1 \ mol \ KOH)/(56.11 \ g \ KOH) )` = 0.183568 mol KOH

Step 4: Solve for Volume

1. Substitute:
   `1.57 \ M=(0.183568 \ mol)/(x \ L)`
2. Move x:
   `x1.57 \ M=0.183568 \ mol`
3. Isolate x:
   `x=(0.183568 \ mol)/(1.57 \ M)`
4. Evaluate:
   `x=0.116922 \ L`

Step 5: Check

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

`0.116922 \ L \approx 0.117 \ L`