Answered By Dhruvin P

This is a stoichiometry problem involving energy. The negative sign in enthalpy indicates energy is released.

Step 1: Find moles of ethane needed

Energy needed = moles × molar enthalpy 1500 kJ = moles × |-1251.0 kJ/mol| moles = 1500 ÷ 1251.0 moles = 1.20 mol

Step 2: Convert moles to mass

Molar mass of ethane (C?H?) = 30.07 g/mol Mass = moles × molar mass = 1.20 mol × 30.07 g/mol = 36.1 g