A mixture of petrol and ethyl alcohol contains 22.0 % alcohol. The density of the mixture is `0.800 g mL^(-1)`. What mass of alcohol is there in 40.0 mL of the mixture?

Options

A. 7.04 gm
B. 4.40 gm
C. 11 gm
D. 15 gm

Answer

To find the mass of alcohol in a 40.0 mL mixture of petrol and ethyl alcohol that contains 22.0% alcohol and has a density of 0.800 g/mL, we can follow these steps:

### Step 1: Calculate the total mass of the mixture
First, we need to determine the mass of the 40.0 mL mixture using its density.

\[ \text{Mass of the mixture} = \text{Volume} \times \text{Density} \]

Given:
- Volume = 40.0 mL
- Density = 0.800 g/mL

\[ \text{Mass of the mixture} = 40.0 \, \text{mL} \times 0.800 \, \text{g/mL} = 32.0 \, \text{g} \]

### Step 2: Calculate the mass of alcohol in the mixture
Next, we can calculate the mass of alcohol in the mixture using the percentage of alcohol.

\[ \text{Mass of alcohol} = \left(\frac{\text{Percentage of alcohol}}{100}\right) \times \text{Mass of the mixture} \]

Given:
- Percentage of alcohol = 22.0%

\[ \text{Mass of alcohol} = \left(\frac{22.0}{100}\right) \times 32.0 \, \text{g} = 7.04 \, \text{g} \]

### Final Answer
The mass of alcohol in 40.0 mL of the mixture is **7.04 g**.

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