Find the molar mass of ethanol,
C
2
H
6
O
C
2
H
6
O
.

BlackTom题目解析

Question

Find the molar mass of ethanol, 
C
2
H
6
O
C
2
H
6
O
 .

BlackTom题目解析

BlackTom AI · Accepted Answer

To begin, I’ll lay out what the question is asking: determine the molar mass of ethanol, whose formula is C2H6O. We’ll break down the contributions from each element using their approximate atomic masses.
Option 1: 29.02 g/mol. This value is far too small for ethanol; it resembles the mass of a small molecule containing mainly carbon and hydrogen, but not enough for two carbons, six hydrogens, and one oxygen. This likely arises from omitting oxygen or miscounting atoms.
Option 2: 45.06 g/mol. This is close to the correct range but slightly low. If one uses rounded atomic masses (for example C = 12.0, H = 1.0, O = 16.0) and does 2×12.0 + 6×1.0 + 16.0, they would get 24.0 + 6.0 + 16.0 = 46.0 g/mol, not 45.06 g/mol. The discrepancy suggests an arithmetic or rounding inconsistency.
Option 3: 46.07 g/mol. This value matches the standard calculated molar mass when using typical atomic masses (C ≈ 12.01, H ≈ 1.008, O ≈ 16.00): 2×12.01 + 6×1.008 + 16.00 = 24.02 + 6.048 + 16.00 ≈ 46.068 g/mol, which rounds to 46.07 g/mol. This aligns with accepted molar mass data for ethanol.
Option 4: 110.0 g/mol. This figure is clearly too large for ethanol and would suggest a molecule with many more atoms or a miscalculation; it is inconsistent with C2H6O’s actual composition.
In summary, the incorrect options arise from undercounting atoms, rounding errors, or arithmetic mistakes, while the correct value requires summing each element’s contribution accurately. The most precise approach uses standard atomic masses and sums to approximately 46.07 g/mol, illustrating why the 46.07 g/mol choice is the appropriate result for ethanol.

Find the molar mass of ethanol, C 2 H 6 O C 2 H 6 O . BlackTom题目解析

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