What mass of propene `(CH_(3)-CH=CH_(2))` is obtained from `34*0g` of 1-iodopropane by treating with ethanolic KOH if the yield of propene is 36 percent?

Answer

To solve the problem of how much mass of propene (CH₃-CH=CH₂) is obtained from 34.0 g of 1-iodopropane when treated with ethanolic KOH, with a yield of 36%, we can follow these steps:

### Step 1: Calculate the number of moles of 1-iodopropane

The molar mass of 1-iodopropane (C₃H₇I) can be calculated as follows:
- Carbon (C): 12.01 g/mol × 3 = 36.03 g/mol
- Hydrogen (H): 1.008 g/mol × 7 = 7.056 g/mol
- Iodine (I): 126.90 g/mol × 1 = 126.90 g/mol

Adding these together:
\[ \text{Molar mass of 1-iodopropane} = 36.03 + 7.056 + 126.90 = 169.986 \text{ g/mol} \approx 170 \text{ g/mol} \]

Now, we can calculate the number of moles of 1-iodopropane:
\[ \text{Number of moles} = \frac{\text{mass}}{\text{molar mass}} = \frac{34.0 \text{ g}}{170 \text{ g/mol}} = 0.2 \text{ moles} \]

### Step 2: Determine the moles of propene produced

From the reaction, we know that 1 mole of 1-iodopropane produces 1 mole of propene. Therefore, the moles of propene produced will also be:
\[ \text{Moles of propene} = 0.2 \text{ moles} \]

### Step 3: Calculate the mass of propene at 100% yield

The molar mass of propene (C₃H₆) is:
- Carbon (C): 12.01 g/mol × 3 = 36.03 g/mol
- Hydrogen (H): 1.008 g/mol × 6 = 6.048 g/mol

Adding these together:
\[ \text{Molar mass of propene} = 36.03 + 6.048 = 42.078 \text{ g/mol} \approx 42 \text{ g/mol} \]

Now, calculate the mass of propene produced at 100% yield:
\[ \text{Mass of propene} = \text{number of moles} \times \text{molar mass} = 0.2 \text{ moles} \times 42 \text{ g/mol} = 8.4 \text{ g} \]

### Step 4: Calculate the actual mass of propene obtained with 36% yield

To find the actual mass of propene obtained with a yield of 36%, we use the formula:
\[ \text{Actual mass} = \text{Theoretical mass} \times \frac{\text{yield}}{100} \]
\[ \text{Actual mass} = 8.4 \text{ g} \times \frac{36}{100} = 3.024 \text{ g} \]

### Final Answer

The mass of propene obtained is **3.024 grams**.

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