mole fraction

Question

In a solution of ethanol (moles 2.0) and water (moles 8.0), mole fraction of ethanol is:

RankGuru · Accepted Answer

1. **Formula**: Mole fraction of a component $i$ ($X_i$) is given by $X_i = \frac{n_i}{\sum n}$, where $n$ is the number of moles.
2. **Given Data**:
   - Moles of Ethanol ($n_{eth}$) = $2.0$
   - Moles of Water ($n_{wat}$) = $8.0$
3. **Total Moles**: $n_{total} = n_{eth} + n_{wat} = 2.0 + 8.0 = 10.0$ moles.
4. **Calculation**: $X_{eth} = \frac{2.0}{10.0} = 0.20$.
5. **Verification**: The sum of mole fractions must be $1$. $X_{wat} = \frac{8.0}{10.0} = 0.80$, and $0.20 + 0.80 = 1.0$.

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mole fraction

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