Question

5. What is the weight /weight percent of a .634m sodium phosphate solution? (3pts)

Answer 1

Given molality (m) of sodium phosphate = 0.634m molar mass of sodium phosphate = 163.90 gmo! molar mass of sodium phosphate is obtained from their elements masses as follows: Atomic masses cher 3 (Na) 3 x 22.99 - 68.97 Na 22.99 gmoit ws(P.) → 1 X 30.97 - 30.97 SP » 30.97 gmoit } 10 →15.99 g moll { 4(0) ► + x 15.99 = 63.96 763.90 I By definition molality, & Number of roles of solute present in I kg of solvent. Ir i 0.634 m (molality) means 0.634 moles of solute} Clie., 0.634 moles of Naz Pog-sodium phosphate) present ins 1 kg 610oog of solvent on Number of moles of Naz POq = 0.634 mol I mol of raz pod = 163-90 grant (from molar) Nazpot mass / 2.0.634 mol Naz Poq = ? g Nazpola 163.90 g Haz Pug 0.634 mol Naz P04 i mol Naz POH = 103.9 g Nazpo So, weight of Naz Poa Present in 0-634 m Nazroq solution is 103.979

Here Nazpoq (sodium phosphate) is solute so weight of solute = 103.9g But weight of solvent = 1000 g (1.e., I kg of solvent) Cassumed from molality calci weight/weight percent (w/w) to . . It is calculated for a solution as follows: ans) - weight of solute + weight of solvent so Solo/) of 0.634m 103.9 g x 100 Sodium phosphate solution 103.98+1000 g : 9.4):). Answer - The weight/ weight percent of a r634 m sodiumphosphate Sduhian is 59.41] %