Analysis of chlorophyll shows that it contains 2.68% Mg. Number of magnesium atoms present in 2.4 g of chlorophyll is

Options

A. `2.68xx6xx10^(21)`
B. `2.68xx6xx10^(23)`
C. `2.68xx6xx10^(20)`
D. `2.68xx6xx10^(20)//24`

Answer

To find the number of magnesium atoms present in 2.4 g of chlorophyll, we can follow these steps:

### Step 1: Calculate the mass of magnesium in 2.4 g of chlorophyll.
Given that chlorophyll contains 2.68% magnesium, we can find the mass of magnesium in 2.4 g of chlorophyll using the formula:

\[ \text{Mass of Mg} = \left( \frac{2.68}{100} \right) \times 2.4 \, \text{g} \]

Calculating this gives:

\[ \text{Mass of Mg} = 0.0268 \times 2.4 = 0.06432 \, \text{g} \]

### Step 2: Calculate the number of moles of magnesium.
To find the number of moles, we use the formula:

\[ \text{Number of moles} = \frac{\text{mass}}{\text{molar mass}} \]

The molar mass of magnesium (Mg) is approximately 24 g/mol. Therefore, we can calculate the number of moles of magnesium:

\[ \text{Number of moles of Mg} = \frac{0.06432 \, \text{g}}{24 \, \text{g/mol}} = 0.00268 \, \text{mol} \]

### Step 3: Calculate the number of magnesium atoms.
Using Avogadro's number, which is approximately \(6.022 \times 10^{23}\) atoms/mol, we can find the total number of magnesium atoms:

\[ \text{Number of atoms} = \text{Number of moles} \times \text{Avogadro's number} \]

Substituting the values:

\[ \text{Number of atoms} = 0.00268 \, \text{mol} \times 6.022 \times 10^{23} \, \text{atoms/mol} \]

Calculating this gives:

\[ \text{Number of atoms} \approx 1.61 \times 10^{21} \, \text{atoms} \]

### Final Answer:
The number of magnesium atoms present in 2.4 g of chlorophyll is approximately \(1.61 \times 10^{21}\) atoms.

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