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34.2 g of sugar was dissolved in water to produce 214.2 g of sugar syrup. Calculate molality and mole fraction of sugar in the syrup. Given C = 12 and O = 16 |
Answer» <html><body><p><strong>Answer:</strong></p><p>1). <a href="https://interviewquestions.tuteehub.com/tag/mole-1100299" style="font-weight:bold;" target="_blank" title="Click to know more about MOLE">MOLE</a> fraction of sugar in syrup = 1/101</p><p></p><p>2). Molality of sugar in syrup = 0.5 mol/ kg</p><p></p><p>>> NOTE : MOLARITY CAN'T BE CALCULATED WITH GIVEN MASS, IT IS ONLY CALCULATED WITH VOLUME, BUT MOLALITY CAN BE CALCULATED.</p><p></p><p>Explanation:</p><p></p><p>1). Mole fraction :</p><p></p><p>>>no. of moles of sugar(<a href="https://interviewquestions.tuteehub.com/tag/solute-1217068" style="font-weight:bold;" target="_blank" title="Click to know more about SOLUTE">SOLUTE</a>)/total moles of solution(solution)</p><p></p><p>(1). sugar = C12H22011</p><p></p><p>Weight of sugar = 34.2g (given)</p><p></p><p>Molar mass of sugar = <a href="https://interviewquestions.tuteehub.com/tag/342-308356" style="font-weight:bold;" target="_blank" title="Click to know more about 342">342</a> g/mol</p><p></p><p>Vol 82</p><p></p><p>>> mole of sugar = 34.2/342 = 1/10 mole</p><p></p><p>(II). Water = H2O</p><p></p><p>Weight of water = 214.2-34.2=180 g Molar mass of water = <a href="https://interviewquestions.tuteehub.com/tag/18-278913" style="font-weight:bold;" target="_blank" title="Click to know more about 18">18</a> g/mol</p><p></p><p>>> mole of water = 180/18 = 10 mole</p><p></p><p>Now,</p><p></p><p>>> Mole fraction = (1/10)/(101/10)</p><p></p><p>= 1/10 × 10/101</p><p></p><p>[Answer] = 1/101 [ Mole fraction</p><p></p><p>is a unit less quantity]</p><p></p><p>Vol 82</p><p></p><p>V</p><p></p><p>2). Molality</p><p></p><p>>> If mass is given in gram then,</p><p></p><p>Molality (weight of solute × 1000)/ = (Molar mass of solute × weight of solvent)</p><p></p><p>Hence,</p><p></p><p>weight of solute (Sugar) = 34.2 g (Given)</p><p></p><p>weight of solvent (water) = 180 g (Given)</p><p></p><p>Molar mass of solute = = 342 g</p><p></p><p>» (34.2 x 1000)/(342 × 180)</p><p></p><p>= 34200/61560</p><p></p><p>= 0.5 mole/Kg [Answer]</p><p></p></body></html> | |