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Grade 11Physical Chemistry

The density of mercury is 13.6 g/ml. calculate approximateiy the diametr of an atom of mercury assuming that each atom is occupying a cube of edge length equal to the diameter of the mercury atom.

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8 Years agoGrade 11
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To find the approximate diameter of a mercury atom based on its density, we can use some fundamental concepts from chemistry and physics. The density of mercury is given as 13.6 g/ml, which tells us how much mass is contained in a specific volume. By using this information, we can estimate the size of a single mercury atom.

Understanding Density and Volume

Density (\( \rho \)) is defined as mass (\( m \)) per unit volume (\( V \)). The formula for density is:

Density (ρ) = Mass (m) / Volume (V)

From this, we can rearrange the formula to find volume:

Volume (V) = Mass (m) / Density (ρ)

Calculating the Volume of Mercury

First, we need to determine the volume occupied by a certain mass of mercury. Let's consider 1 mole of mercury, which has a mass of approximately 200.59 grams. Using the density of mercury, we can calculate the volume:

  • Mass of 1 mole of mercury = 200.59 g
  • Density of mercury = 13.6 g/ml

Now, substituting these values into the volume formula:

Volume (V) = 200.59 g / 13.6 g/ml ≈ 14.75 ml

Finding the Number of Atoms in a Mole

Next, we need to find out how many atoms are in 1 mole of mercury. According to Avogadro's number, there are approximately \( 6.022 \times 10^{23} \) atoms in a mole. Therefore:

  • Number of atoms in 1 mole = \( 6.022 \times 10^{23} \) atoms

Calculating the Volume Occupied by One Atom

To find the volume occupied by a single mercury atom, we divide the total volume of 1 mole by the number of atoms in that mole:

Volume per atom = Total Volume / Number of Atoms

Volume per atom = 14.75 ml / \( 6.022 \times 10^{23} \) atoms ≈ 2.45 \times 10^{-23} ml

Converting Volume to Cubic Centimeters

Since 1 ml is equivalent to 1 cm³, we can express the volume per atom in cubic centimeters:

Volume per atom ≈ 2.45 \times 10^{-23} cm³

Relating Volume to Diameter

Assuming that each mercury atom occupies a cube, we can find the edge length of this cube, which will be equal to the diameter of the atom. The volume of a cube is given by:

Volume = edge length³

To find the edge length, we take the cube root of the volume:

Edge length = \( \sqrt[3]{Volume} \)

Edge length = \( \sqrt[3]{2.45 \times 10^{-23} cm³} ≈ 2.92 \times 10^{-8} cm

Converting to Nanometers

To express this in a more convenient unit, we can convert centimeters to nanometers (1 cm = \( 10^{7} \) nm):

Diameter ≈ 2.92 \times 10^{-8} cm × 10^{7} nm/cm ≈ 0.292 nm

Thus, the approximate diameter of a mercury atom is around 0.292 nanometers. This calculation illustrates how we can derive atomic dimensions from macroscopic properties like density, providing a fascinating link between the microscopic and macroscopic worlds.