Answer to Question #70171 in General Chemistry for Desiree Berger

Question

1. In the presence of some metals, ethylene (C2H4) and hydrogen gas react to form ethane (C2H6) according to the following thermochemical equation:
C2H4(g) + H2(g)---> C2H6(g) triangle H°= -136.98 kJ
If the molar mass of ethylene is 28.05 g/mol, how much heat is liberated when 100.0 g of ethylene reacts?


2. How much it was prior to convert 20.0 g of ice at -50.0°C to liquid water at 0.0°C?
The specific heat of ice is 2.06 J/(g•°C) and the heat of fusion of water is 334 J/g.


3. Under certain conditions, nitrogen gas and oxygen gas react to form the toxic brown gas nitrogen dioxide: N2(g) + 2 O2(g) ---> 2 NO2(g). For this reaction, triangle H°= 66.2 kJ and triangle S°= -121.81 J/K; calculate triangle G° at standard conditions (298 K and 1 atm) and determined if a reaction is spontaneous, nonspontaneous, or an equilibrium at these conditions.