Answer:
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.
Answer:
Explanation:
Remark
First of all you have to identify what is happening. You make the following observations.
The solution in the test tube in a cold water bath is colorless.
As you add heat, the color changes from colorless to brown.
What you are told
N2O4 is colorless
NO2 is brownish red.
What you conclude
The reaction is endothermic. That means it requires heat to happen. An endothermic reaction is
A + Heat ===> B
So you have three possible correct answers
N2O4 + 14 kCal ===> 2NO2
N2O4 ====> 2NO2 dH = 14 kCal
N2O4 ====> 2NO2 - 14 kCal
I can't read the last 4 equations.
Other answers
As the temperature increased, the N2O4 became less.
As the temperature increased, the products were favored. (color change)
The reaction is exothermic (gives off heat) when the reaction goes from
NO2 - Heat ===> N2O2
Molality is the moles of solute per kg of solvent.
Moles of NH₄Cl = 2.4 / (14 + 4 x 1 + 35.5)
= 0.0448 mole
Molality = 0.0448 / (19.4 / 1000)
= 2.31 m
After the first 30 minutes,
dT = 75-60
= 15
dt = 30 mins
k = (15/60) * (60 - 38)
k = 5.5
After 60 minutes,
dT = 60 - T
dt = 30
(60 - T)/30 = 5.5(T - 38)
60 - T = 165T - 6270
166T = 6330
T = 38.13°F
Answer:
-368.62 kJ/mol
Explanation:
[(2 x - 470.11 kJ/mol) ( 0kJ/mol)] - [ 2 x -285.8 kJ/mol) (2x 0 kj/mol)] = -368.62 kJ/mol