The formula mass of a compound is always the same as its molecular mass

Answer

To determine whether the statement "The formula mass of a compound is always the same as its molecular mass" is true or false, we can follow these steps:

### Step 1: Define Formula Mass
Formula mass is defined as the sum of the molar masses of all the atoms present in the empirical formula of a compound.

### Step 2: Define Molecular Mass
Molecular mass is the sum of the molar masses of all the atoms present in the molecular formula of a compound.

### Step 3: Understand Empirical Formula
The empirical formula represents the simplest whole number ratio of the atoms in a compound.

### Step 4: Example of Glucose
Take glucose as an example, which has the molecular formula C6H12O6.
- The empirical formula for glucose is CH2O.
- Calculate the formula mass using the empirical formula:
- Carbon (C): 12 g/mol
- Hydrogen (H): 1 g/mol (2 H atoms = 2 g/mol)
- Oxygen (O): 16 g/mol
- Formula mass = 12 + 2 + 16 = 30 g/mol.

### Step 5: Calculate Molecular Mass of Glucose
Now, calculate the molecular mass using the molecular formula C6H12O6:
- Molecular mass = (6 × 12) + (12 × 1) + (6 × 16)
- Molecular mass = 72 + 12 + 96 = 180 g/mol.

### Step 6: Compare Formula Mass and Molecular Mass
From the calculations:
- Formula mass of glucose = 30 g/mol
- Molecular mass of glucose = 180 g/mol

### Step 7: Conclusion
Since the formula mass (30 g/mol) and molecular mass (180 g/mol) are not the same, we conclude that the statement "The formula mass of a compound is always the same as its molecular mass" is **false**.

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