The empirical formula for copper sulfide is CuS Cu2S Cu2S2 CuS2 the percent compositon of copper sulfide is 50% copper and 50%sulfur 54% copper and 46% sulfur 80% copper and 20% sulfur 20% copper and 80% sulfur
The correct answer and explanation is :
The correct empirical formula for copper sulfide depends on the experimental determination of its composition. However, the most common forms of copper sulfide are CuS and Cu₂S.
The correct answer for the percent composition of copper sulfide is:
Cu₂S (Copper(I) sulfide) with 80% Copper and 20% Sulfur.
Explanation
The empirical formula represents the simplest whole-number ratio of atoms in a compound. Copper sulfide exists in different forms, but we will analyze the percent composition of Cu₂S.
Step 1: Determine the Molar Mass of Cu₂S
- Copper (Cu) atomic mass = 63.55 g/mol
- Sulfur (S) atomic mass = 32.07 g/mol
- Cu₂S contains 2 copper atoms and 1 sulfur atom:
[
\text{Molar mass of Cu₂S} = (2 \times 63.55) + (1 \times 32.07)
]
[
= 127.10 + 32.07 = 159.17 \text{ g/mol}
]
Step 2: Calculate Percent Composition
- % Copper =
[
\left( \frac{127.10}{159.17} \right) \times 100 = 79.9\% \approx 80\%
] - % Sulfur =
[
\left( \frac{32.07}{159.17} \right) \times 100 = 20.1\% \approx 20\%
]
Thus, the percent composition of Cu₂S is approximately 80% copper and 20% sulfur, making it the correct answer.
Why Other Options Are Incorrect?
- CuS (Copper(II) sulfide) has 54% Cu and 46% S, so it is incorrect.
- CuS₂ and Cu₂S₂ are not standard empirical formulas and do not match the given choices.
Thus, the correct empirical formula is Cu₂S with 80% Copper and 20% Sulfur.
Here is the scientific diagram illustrating the composition of Copper(I) Sulfide (Cu₂S), showing the molecular representation, atomic masses, and percentage composition.