Moving to another question will save this response. Question 15 Calculate the molar mass of magnesium chloride, MgCl
. 125.9 g/mole 59.76 g/mole 70.90 g/mole 95.21 g/mole 24.31 g/mole
The Correct Answer and Explanation is:
Correct Answer: 95.21 g/mole
To calculate the molar mass of magnesium chloride (MgCl₂), you need to add the atomic masses of all atoms present in the compound.
Step-by-Step Calculation:
Magnesium chloride (MgCl₂) consists of:
- 1 magnesium (Mg) atom
- 2 chlorine (Cl) atoms
Using standard atomic masses:
- Atomic mass of magnesium (Mg) = 24.31 g/mol
- Atomic mass of chlorine (Cl) = 35.45 g/mol
Now, multiply the atomic mass of chlorine by 2 because there are two chlorine atoms in MgCl₂:
Molar mass of MgCl₂ = (1 × 24.31 g/mol) + (2 × 35.45 g/mol)
= 24.31 g/mol + 70.90 g/mol
= 95.21 g/mol
This is the total mass of one mole of magnesium chloride.
Explanation:
Molar mass refers to the mass of one mole of a substance. A mole is a standard unit in chemistry that represents 6.022×10236.022 \times 10^{23}6.022×1023 particles of a substance, whether atoms, molecules, or ions. In the case of MgCl₂, each formula unit contains one magnesium atom and two chlorine atoms. Magnesium is a metal from group 2 of the periodic table and forms a +2 ion. Chlorine is a halogen and typically forms a -1 ion. Therefore, two chloride ions are required to balance one magnesium ion, resulting in the neutral compound MgCl₂.
Calculating the molar mass is essential for many chemical applications. It helps chemists determine how much of each element is in a compound and is useful in stoichiometric calculations for reactions, making it a fundamental skill in both academic and practical chemistry.
