Mole fraction
Mole fraction is a Science & Technology concept from the MPSC syllabus, tested in 3 past MPSC questions (2021, 2023). Below are those real questions with their correct answers and explanations, plus the concepts worth being comfortable with first.
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180 ग्रॅम अॅसेटिक आम्ल (CH3COOH) आणि 180 ग्रॅम पाणी (H2O) एकमेकांत मिसळले. तयार झालेल्या द्रावणात अॅसेटिक आम्लाचा मोल फॅक्शन ______ इतका असेल. [H = 1, C = 12, O = 16] 180 g of acetic acid (CH3COOH) is mixed with 180 g of water (H2O). The mole fraction of acetic acid in the resultant solution is [H = 1, C = 12, O = 16]
Molar mass of CH3COOH = 12+3+12+16+16+1 = 60 g/mol. Moles of CH3COOH = 180 / 60 = 3. Molar mass of H2O = 18 g/mol. Moles of H2O = 180 / 18 = 10. Mole fraction of acetic acid = Moles of acid / Total moles = 3 / (3 + 10) = 3 / 13 = 0.23.
समुद्रपातळीवर असलेल्या प्रयोगशाळेत वापरण्यासाठी, वर्षाच्या कोणत्याही दिवशी खालीलपैकी सगळ्यात योग्य संहति एकक/एकके _________ हे/ही आहे/आहेत. On any day of the year, to use in laboratories at sea level the most correct concentration unit/s is/are _________.
Molality is independent of temperature because it is expressed in terms of mass of solvent (kg), whereas molarity and normality depend on volume which varies with temperature.
32 ग्रॅम मिथेन (रेणु वस्तुमान 16 g/mol) आणि 192 ग्रॅम ऑक्सिजन (रेणु वस्तुमान 32 g/mol) एकत्र मिसळले. हे दोन वायू जर एकमेकांशी रासायनिक प्रक्रिया करत नसतील तर मिथेन वायूचे मोल फ्रॅक्शन किती ? / 32 g of methane (molar mass 16 g/mol) is mixed with 192 g of oxygen (molar mass 32 g/mol). Presuming that these gases donot react with each other, what is the mole fraction of methane ?
Moles of methane = 32/16 = 2 moles. Moles of oxygen = 192/32 = 6 moles. Total moles = 2 + 6 = 8 moles. Mole fraction of methane = Moles of methane / Total moles = 2/8 = 0.25 (or 1/4).