CH-1975
The mole
Chemistry · Secondary 4 · Hard · The mole
A 2.00 dm³ sample of river water is analysed using the Winkler method.
In the final step, 3.20 × 10⁻³ mol of thiosulfate ions, S₂O₃²⁻, are used.
The overall ratio is 1 mol O₂ : 4 mol S₂O₃²⁻.
What is the concentration of dissolved oxygen in the water sample, in mg/dm³?
In the final step, 3.20 × 10⁻³ mol of thiosulfate ions, S₂O₃²⁻, are used.
The overall ratio is 1 mol O₂ : 4 mol S₂O₃²⁻.
What is the concentration of dissolved oxygen in the water sample, in mg/dm³?
- 12.8 mg/dm³
- 25.6 mg/dm³
- 32.0 mg/dm³
- 64.0 mg/dm³
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