Calculate the molar mass of magnesium chloride, MgCl 2.
The correct answer and explanation is :
To calculate the molar mass of magnesium chloride (MgCl₂), we need to sum up the atomic masses of all the atoms in the compound. Magnesium chloride consists of one magnesium (Mg) atom and two chlorine (Cl) atoms.
Step 1: Find the atomic masses of the elements involved.
- Magnesium (Mg) has an atomic mass of approximately 24.305 g/mol.
- Chlorine (Cl) has an atomic mass of approximately 35.45 g/mol.
Step 2: Multiply the atomic mass of each element by the number of atoms of that element in the formula.
- There is 1 magnesium atom in MgCl₂, so the mass of magnesium is:
[
1 \times 24.305 = 24.305 \, \text{g/mol}
] - There are 2 chlorine atoms in MgCl₂, so the mass of chlorine is:
[
2 \times 35.45 = 70.90 \, \text{g/mol}
]
Step 3: Add the masses of all the atoms together to find the molar mass of MgCl₂.
[
\text{Molar mass of MgCl}_2 = 24.305 + 70.90 = 95.205 \, \text{g/mol}
]
Explanation:
The molar mass of a compound is the sum of the atomic masses of all the atoms in its formula, calculated in grams per mole (g/mol). In this case, magnesium chloride (MgCl₂) consists of one magnesium atom and two chlorine atoms. The atomic mass of magnesium is approximately 24.305 g/mol, and the atomic mass of chlorine is approximately 35.45 g/mol. By multiplying the atomic masses by the number of atoms of each element in the compound (one magnesium atom and two chlorine atoms), we find the total molar mass of MgCl₂ to be 95.205 g/mol.
This value represents the mass of one mole of magnesium chloride. The molar mass is a crucial concept in chemistry because it allows chemists to convert between the number of moles of a substance and its mass, making it easier to carry out stoichiometric calculations in chemical reactions.