Please help, and solve the problem in kJ

1. Exothermic.

2. Yes, released.

3. 38.65KJ of heat is released.

Explanation:

The equation for the reaction is given below:

2NO2 —> N2O4 ΔH = –55.3KJ

1. The sign of the enthalpy change, ΔH tells whether the reaction is endothermic or exothermic. Since the sign of the enthalpy change, ΔH is negative, the reaction is exothermic.

2. The negative sign indicate that heat is released to the surrounding. Since the reaction is generally an exothermic reaction, 64.3g of NO2 will also release heat to the surroundings.

3. Molar mass of NO2 = 14 + (16x2) = 46g/mol

Mass of NO2 from the balanced equation = 2 x 46 = 92g.

From the balanced equation above:

92g of NO2 reacted to release –55.3KJ of heat.

Therefore, 64.3g of NO2 will react to release = (64.3 x –55.3)/92 = 38.65KJ of heat.

Therefore, 38.65KJ of heat is released.

yes the answer is total mass in unchanged   : )