MCQ Detailed View

The mole concept is fundamental in chemistry for converting between mass and the amount of a substance. The formula to calculate the number of moles is:

n=Mass of substance (g)Molar mass (g/mol)n = \frac{\text{Mass of substance (g)}}{\text{Molar mass (g/mol)}}n=Molar mass (g/mol)Mass of substance (g)

In this problem, the substance is carbon disulfide (CS₂), and we are given 9.5 grams of it.

1️⃣ Step 1 – Calculate Molar Mass of CS₂:

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  Carbon (C) = 12 g/mol

  
  


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  Sulfur (S) = 32 g/mol × 2 = 64 g/mol

  
  

$$\text{Molar mass}=12+64=76\text{g/mol}$$

2️⃣ Step 2 – Apply the formula:

n=9.576n = \frac{9.5}{76}n=769.5 $$n=0.125\text{moles}$$

So, 9.5 grams of CS₂ contains 0.125 moles of the compound.

❌ Why Other Options Are Incorrect:

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  1.5 moles: This would correspond to 114 g of CS₂, much larger than the given mass.

  
  


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  0.25 moles: This would require 19 g of CS₂, which is not the case here.

  
  


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  None of These: Incorrect because the calculated answer (0.125) is listed.

  
  

Hence, the correct answer is Option C (0.125 moles). This example illustrates the importance of understanding molar mass and applying the mass-to-moles conversion formula in stoichiometric calculations.