If you mixed 20 mL of 50 mM sodium acetate (NaOAc) with 30 mL of 25 mM glucose, what would be the concentration of each in the final solution?
A. 50 mM NAOAc, 25 mM Glucose
B. 20 mm NaOAc, 15 mM Glucose
C. 30 mm NaOAc, 20 mM Glucose
D. 40 mM NaOAc, 10 mM Glucose

Mixing Solutions: Sodium Acetate and Glucose

When you mix two solutions of different concentrations and volumes, the final concentrations of each solute can be calculated using basic dilution formulas.

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📌 Problem Statement

You mix 20 mL of 50 mM sodium acetate (NaOAc) with 30 mL of 25 mM glucose. What is the final concentration of each in the resulting solution?

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Step-by-Step Calculation

Step 1: Use the Dilution Formula

The final concentration is calculated using:

C₁V₁ + C₂V₂ = Total amount of solute / Total volume

Sodium Acetate (NaOAc)

C₁ = 50 mM, V₁ = 20 mL
Total moles of NaOAc = 50 × 20 = 1000 µmol

Glucose

C₂ = 25 mM, V₂ = 30 mL
Total moles of glucose = 25 × 30 = 750 µmol

Total Volume

Total volume = 20 mL + 30 mL = 50 mL

Final Concentrations

• NaOAc: 1000 µmol / 50 mL = 20 mM
• Glucose: 750 µmol / 50 mL = 15 mM

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Final Answer: B. 20 mM NaOAc, 15 mM Glucose

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Key Takeaways

• Always convert to total µmol before dividing by final volume.
• This approach works for any solute-solvent mixing scenario.
• Double-check units to avoid miscalculation.