Answer:
See explanation
Explanation:
In a chemical reaction, a particular reaction path may be favoured due to the fact that it is energetically more favourable(lower energy sigma complex is formed).
The more the resonance structures produced in a particular reaction pathway, the more energetically favourable it is.
In the chlorination of bromobenzene, ortho attack and para attack are preferred because each of these pathways involves a sigma complex with__4________resonance structures. Attack at the meta position involves formation of a sigma complex with only____3_______ resonance structures. The reaction will proceed more rapidly via the_____lower_______ energy sigma complex, so attack takes place at the ortho and para positions in preference to the meta position.
Answer:
B. - 210 kJ
Explanation:
<em>∵ ΔHrxn = ∑(bond energies)products - ∑(bond energies)reactants.</em>
- The bond formation in the products releases energy (exothermic).
- The bond breaking in the reactants requires energy (endothermic).
The products:
- H₂O contains 2 O-H (- 459 kJ/mol) bonds.
- O₂ contain 1 O=O (- 494 kJ/mol) bond.
The reactants:
- H₂O₂ contain 2 O–H (459 kJ/mol) bonds and 1 O–O (142 kJ/mol) bond.
∵ ΔHrxn = ∑(bond energies)products - ∑(bond energies)reactants.
<em>∴ ΔHrxn = [2 (2 x (O–H bond energy) + (1 x (O=O bond energy)] - 2 [(2 x (O–H bond energy) + (1 x (O–O bond energy)] </em>= [2 (2 x - 459 kJ/mol) + (1 x - 494 kJ/mol)] - 2 [(2 x 459 kJ/mol) + (1 x 142 kJ/mol)] = (- 2330 kJ) + (2120 kJ) = <em>- 210 kJ.</em>
Answer:
When an object is heated up, its particles gain more kinetic energy and hence its internal energy increases. A change in state will also result in a change in internal energy.
When an object cools down, heat is withdrawn from it. Hence, the entropy of the object decreases. But the decrease in entropy leads to the transfer of energy to the surrounding.
I hope this helps you! Good luck with school! :D
Condensation<span>.
</span><span>Think of the water cycle in terms of raining/other forms of precipitation. Water condenses - or turns back into liquid from water vapor - to form into clouds.</span>
the molecules in a liquid are loosely arranged, and are arranged randomly
