If the density of some lake water is 1.25 g mL -1 and contains 92 g of Na + ions per kg of water, calculate the molality of Na + ions in the lake.

Question

If the density of some lake water is 1.25 g mL -1 and contains 92 g of Na + ions per kg of water, calculate the molality of Na + ions in the lake.,

MARKS App · Accepted Answer

Molality of Na + ions (m) = Number of moles of Na + ions Mass of water in kg = 92 g / 23 g mol − 1 1 kg = 4 mol kg − 1 or 4 m