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. (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

Molality of textNa text+ ions (m) text= ( textNumber textof textmoles textof textNa text+ textions/ textMass textof textwater textin textkg) =((92 mathrm~g) /(23 mathrm~g mathrm~mol-1)/(1 mathrm~kg)) text= text4 textmol textkg- text1 textor text4 textm

Q. 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.

Molality of $Na^{+}$ ions (m)

$= \frac{Number of moles of Na ^{+} ions}{Mass of water in kg}$

$= \frac{( 92 g ) / ( 23 g mol ^{- 1} )}{( 1 kg )}$

$= 4 mol kg^{- 1} or 4 m$

Q. 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.

Molality of Na+ ions (m) =MassofwaterinkgNumberofmolesofNa+ions​ =(1 kg)(92 g)/(23 g mol−1)​ =4molkg−1or4m

Q. 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.

Molality of $Na^{+}$ ions (m)

$= \frac{Number of moles of Na ^{+} ions}{Mass of water in kg}$

$= \frac{( 92 g ) / ( 23 g mol ^{- 1} )}{( 1 kg )}$

$= 4 mol kg^{- 1} or 4 m$