Calculate mass of one atom of calcium in gram.

Answer

To calculate the mass of one atom of calcium in grams, we can follow these steps:

### Step 1: Understand the relationship between moles and atoms
We know that one mole of any substance contains Avogadro's number of particles (atoms, in this case). Avogadro's number (Na) is approximately \(6.022 \times 10^{23}\) atoms/mole.

### Step 2: Find the molar mass of calcium
The molar mass of calcium (Ca) is given as 40 grams/mole. This means that one mole of calcium weighs 40 grams.

### Step 3: Calculate the mass of one atom of calcium
To find the mass of one atom of calcium, we can use the formula:
\[ \text{Mass of one atom} = \frac{\text{Molar mass of calcium}}{\text{Avogadro's number}} \]
Substituting the values we have:
\[ \text{Mass of one atom} = \frac{40 \text{ g}}{6.022 \times 10^{23} \text{ atoms/mole}} \]

### Step 4: Perform the calculation
Now we perform the division:
\[ \text{Mass of one atom} = \frac{40}{6.022 \times 10^{23}} \approx 6.641 \times 10^{-23} \text{ grams} \]

### Final Answer
The mass of one atom of calcium is approximately \(6.641 \times 10^{-23}\) grams.

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