Answer :
To determine the percentage composition of each element in magnesium chloride, MgCl₂, let's follow the steps outlined below:
1. Identify the Atomic Weights:
- Magnesium (Mg) has an atomic weight of 24.
- Chlorine (Cl) has an atomic weight of 35.5.
2. Determine the Number of Atoms:
- In the compound MgCl₂, there is 1 atom of Magnesium (Mg).
- There are 2 atoms of Chlorine (Cl).
3. Calculate the Molar Mass of MgCl₂:
- The molar mass is the sum of the atomic weights of all atoms in the compound.
- Molar mass of MgCl₂ = (1 × 24) + (2 × 35.5) = 24 + 71 = 95.
4. Calculate the Percentage Composition:
- Percentage of Magnesium (Mg):
- The contribution of Mg to the molar mass is 24.
- Percentage of Mg = (Contribution of Mg / Molar mass of MgCl₂) × 100
- Percentage of Mg = (24 / 95) × 100 ≈ 25.26%
- Percentage of Chlorine (Cl):
- The contribution of Cl to the molar mass is 71 (since 2 Cl atoms each contribute 35.5).
- Percentage of Cl = (Contribution of Cl / Molar mass of MgCl₂) × 100
- Percentage of Cl = (71 / 95) × 100 ≈ 74.74%
Therefore, in magnesium chloride (MgCl₂), magnesium constitutes approximately 25.26%, and chlorine constitutes approximately 74.74%.
1. Identify the Atomic Weights:
- Magnesium (Mg) has an atomic weight of 24.
- Chlorine (Cl) has an atomic weight of 35.5.
2. Determine the Number of Atoms:
- In the compound MgCl₂, there is 1 atom of Magnesium (Mg).
- There are 2 atoms of Chlorine (Cl).
3. Calculate the Molar Mass of MgCl₂:
- The molar mass is the sum of the atomic weights of all atoms in the compound.
- Molar mass of MgCl₂ = (1 × 24) + (2 × 35.5) = 24 + 71 = 95.
4. Calculate the Percentage Composition:
- Percentage of Magnesium (Mg):
- The contribution of Mg to the molar mass is 24.
- Percentage of Mg = (Contribution of Mg / Molar mass of MgCl₂) × 100
- Percentage of Mg = (24 / 95) × 100 ≈ 25.26%
- Percentage of Chlorine (Cl):
- The contribution of Cl to the molar mass is 71 (since 2 Cl atoms each contribute 35.5).
- Percentage of Cl = (Contribution of Cl / Molar mass of MgCl₂) × 100
- Percentage of Cl = (71 / 95) × 100 ≈ 74.74%
Therefore, in magnesium chloride (MgCl₂), magnesium constitutes approximately 25.26%, and chlorine constitutes approximately 74.74%.
