Which of the following weighs the most?

The correct option is One mole of sodium.

To determine which of the given options weighs the most, we need to calculate the mass of each option in grams. Let's calculate the mass for each option step-by-step:

1. One g-atom of nitrogen:
The term "g-atom" (gram-atom) refers to one mole of monoatomic element atoms. Therefore, 1 g-atom of nitrogen is equal to 1 mole of nitrogen atoms (N).
The atomic mass of nitrogen (N) is approximately 14 g/mol.
Therefore, the mass of one g-atom of nitrogen is:
$$\text{Mass}=14\text{ g}$$

2. One mole of water (H₂O):
The molar mass of water (H₂O) is calculated as:
$$(2\times 1\text{ g/mol for H})+(1\times 16\text{ g/mol for O})=18\text{ g/mol}$$
Therefore, the mass of one mole of water is:
$$\text{Mass}=18\text{ g}$$

3. One mole of sodium (Na):
The atomic mass of sodium (Na) is approximately 23 g/mol.
Therefore, the mass of one mole of sodium is:
$$\text{Mass}=23\text{ g}$$

4. One molecule of H₂SO₄:
The molecular mass of sulfuric acid (H₂SO₄) is 98 amu (atomic mass units).
The mass of a single molecule of H₂SO₄ in grams is extremely small:
$$\text{Mass}=\frac{98}{6.022\times {10}^{23}}\text{ g}\approx 1.63\times {10}^{-22}\text{ g}$$

Comparing the calculated masses:
• One g-atom of nitrogen = 14 g
• One mole of water = 18 g
• One mole of sodium = 23 g
• One molecule of H₂SO₄ ≈ 1.63 × 10^-22 g

Clearly, 23 g (One mole of sodium) is the largest value among all the options. Thus, one mole of sodium weighs the most.