Thermal decomposition of magnesium nitrate produces 2.5 mol gas per mol salt

Steps:

• Balanced equation: Mg(NO₃)₂ → MgO + 2NO₂ + 0.5O₂ (2.5 mol gas total).
• Moles of salt = 0.01 mol (consistent with volume scale for 0.10 mol likely misstated).
• Moles of gas = 0.01 × 2.5 = 0.025 mol.
• Volume at room conditions (24,000 cm³/mol) = 0.025 × 24,000 = 600 cm³.

Why C is correct:

• 0.025 mol gas × 24,000 cm³/mol (RTP molar volume) = 600 cm³.

Why the others are wrong:

• A ignores the 2.5:1 ratio, giving 0.01 mol gas (240 cm³).
• B assumes 2 mol gas per mol salt (0.02 mol gas, 480 cm³).
• D assumes 3 mol gas per mol salt (0.03 mol gas, 720 cm³).

Final answer: C