Answer: "physical change" .
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This would be a "physical change" . ________________________________________________________
<u>Note</u>: This would change from a "solid" to a "liquid" / mere rearrangement of molecules/ NOT a new chemical substance—hence, a "physical change".
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Answer:
-514 kJ/mol
Explanation:
The bond enthalpy which is also known as bond energy can be defined as the amount of energy needed to split one mole of the stated bond. The change in enthalpy of a given reaction can be estimated by subtracting the sum of the bond energies of the reactants from the sum of the bond energies of the products.
For the given chemical reaction, the change in enthalpy of the reaction is:
Δ
[2(409) + 4(388) + 3(496) - 4(630) - 4(463)] kJ/mol = 818 + 1552 + 1488 - 2520 - 1852 = -514 kJ/mol
Answer:
When hydrogen reacts with chlorine, hydrogen chloride is formed. Hydrogen chloride is a gas, and has the formula HCl(g).
When hydrogen chloride dissolves in water, hydrochloric acid is formed. This has the same formula, but you can tell the difference because of the state symbol (aq), which stands for ‘aqueous’. The formula is written as HCl(aq).
Hydrogen chloride is made from molecules. The hydrogen atom and the chlorine atom are joined by a covalent bond. When hydrogen chloride forms hydrochloric acid, the molecules split into ions.
HCl(aq) → H+(aq) + Cl-(aq)
The H+ ions make this aqueous solution acidic. The solution also conducts electricity because it contains ions that are free to move.
However, when hydrogen chloride gas dissolves in a solvent called methylbenzene, the molecules do not split up. A solution of HCl in methylbenzene does not contain hydrogen ions, so it is not acidic. The solution also has a low electrical conductivity.
The correct answer is true. It was introduced by Svante Arrhenius that activation energy is minimum amount of energy needed to be supplied or released for a chemical reaction to proceed. It is the energy needed to overcome for a reaction to occur.
