Question

Дано термохимическое уравнение горения этилена: C2H4+3O2=2CO2+2H2O+1400 Дж. Сколько теплоты выделяется, если в реакциях вступило 336 л. кислорода! !!

Answer 1

336*1400/67,2=7000кДж

Answer 2

Calculation of Heat Released in the Combustion Reaction

The given thermochemical equation for the combustion of ethylene (C2H4) is:

C2H4 + 3O2 → 2CO2 + 2H2O + 1400 kJ

To calculate the amount of heat released in the reaction when 336 liters of oxygen (O2) is involved, we need to use the stoichiometry of the reaction.

From the balanced equation, we can see that 1 mole of ethylene reacts with 3 moles of oxygen to produce 2 moles of carbon dioxide and 2 moles of water. Therefore, the molar ratio between ethylene and oxygen is 1:3.

To find the number of moles of oxygen, we can use the ideal gas law:

PV = nRT

Where: P = pressure (assume standard pressure, 1 atm) V = volume of gas (336 liters) n = number of moles R = ideal gas constant (0.0821 L·atm/(mol·K)) T = temperature (assume standard temperature, 273 K)

Using the ideal gas law, we can calculate the number of moles of oxygen:

n = PV / RT n = (1 atm) * (336 L) / (0.0821 L·atm/(mol·K) * 273 K) n ≈ 14.7 moles

Since the molar ratio between ethylene and oxygen is 1:3, the number of moles of ethylene involved in the reaction is:

(1/3) * 14.7 moles ≈ 4.9 moles

Now, we can calculate the amount of heat released in the reaction using the given value of 1400 kJ:

Heat released = 1400 kJ * (4.9 moles / 1 mole) Heat released ≈ 6860 kJ

Therefore, approximately 6860 kJ of heat is released when 336 liters of oxygen react in the combustion of ethylene.

Please note that the given thermochemical equation states the heat released in the reaction as 1400 kJ, not 1400 J as mentioned in the question. I have used the given value of 1400 kJ in the calculation.