The percentage composition of elements in a compound is calculated from the molecular formula of the compound. The molecular mass of a compound is calculated from the atomic masses of the various elements present in the compound. The percentage of mass of each element is then calculated with the help of the following relation. Percentage mass of the element in the compound.
`("Mass of the element")/("Mass of the compound")`
Calculate the mass of carbon present in 2 g of carbon dioxide.

Options

A. 12g
B. 6 g
C. `0.545g`
D. `5.45g`

Explanation

To calculate the mass of carbon present in 2 grams of carbon dioxide (CO2), we will follow these steps:

### Step 1: Determine the molecular formula of carbon dioxide.
The molecular formula of carbon dioxide is CO2, which consists of:
- 1 carbon atom (C)
- 2 oxygen atoms (O)

### Step 2: Find the atomic masses of carbon and oxygen.
- The atomic mass of carbon (C) is approximately 12 g/mol.
- The atomic mass of oxygen (O) is approximately 16 g/mol.

### Step 3: Calculate the molecular mass of carbon dioxide (CO2).
The molecular mass of CO2 can be calculated as follows:
- Mass of 1 carbon atom = 12 g/mol
- Mass of 2 oxygen atoms = 2 × 16 g/mol = 32 g/mol

Now, add these masses together:
\[ \text{Molecular mass of CO2} = 12 \, \text{g/mol} + 32 \, \text{g/mol} = 44 \, \text{g/mol} \]

### Step 4: Calculate the percentage composition of carbon in CO2.
To find the percentage mass of carbon in CO2, use the formula:
\[ \text{Percentage mass of carbon} = \left( \frac{\text{Mass of carbon}}{\text{Mass of CO2}} \right) \times 100 \]

Substituting the values:
\[ \text{Percentage mass of carbon} = \left( \frac{12}{44} \right) \times 100 \approx 27.27\% \]

### Step 5: Calculate the mass of carbon in 2 grams of carbon dioxide.
Now, we can find the mass of carbon in 2 grams of CO2 using the percentage we calculated:
\[ \text{Mass of carbon} = \left( \frac{12}{44} \right) \times 2 \, \text{g} \]

Calculating this gives:
\[ \text{Mass of carbon} = \left( \frac{12}{44} \right) \times 2 \approx 0.545 \, \text{g} \]

### Final Answer:
The mass of carbon present in 2 grams of carbon dioxide is approximately **0.545 grams**.

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