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3 Quantitative chemistry

3 Quantitative chemistry

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Question 25

An agricultural scientist investigated the total dissolved solids (TDS) in a runoff sample collected from a commercial hydroponic greenhouse.

The scientist used the following procedure:

  1. Filter the runoff sample to remove any suspended organic debris.
  2. Record the mass of a clean, dry porcelain crucible.
  3. Pipette exactly 40 cm3 of the filtered runoff into the crucible.
  4. Heat the crucible gently using a Bunsen burner until all the liquid has evaporated to dryness.
  5. Re-weigh the crucible and the remaining dry mineral salts.

The recorded measurements are shown in the table below:

MeasurementMass (g)
Mass of empty crucible54.32
Mass of crucible and dry mineral salts54.58

Calculate the concentration of dissolved mineral salts in g dm−3\text{g dm}^{-3}g dm−3 (mass in 1000 cm3) of this runoff sample.

[3]
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3 Quantitative chemistry Questions

  1. GCSE
  2. /Chemistry
  3. /3 Quantitative chemistry

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