Answer:
-125 kJ
Explanation:
You calculate the energy required to break all the bonds in the reactants. Then you subtract the energy to break all the bonds in the products.
H₂C=CH₂ + H₂ ⟶ H₃C-CH₃
Bonds: 4C-H + 1C=C 1H-H 6C-H + 1C-C
D/kJ·mol⁻¹: 413 612 436 413 347
The formula relating ΔHrxn and bond dissociation energies (D) is
ΔHrxn = Σ(Dreactants) – Σ(Dproducts)
(Note: This is an exception to the rule. All other thermochemical reactions are “products – reactants”. With bond energies, it’s “reactants – products”. The reason comes from the way we define bond energies.)
<em>For the reactant</em>s:
Σ(Dreactants) = 4 × 413 + 1 × 612 + 1 × 436 = 2700 kJ
<em>For the products:</em>
Σ(Dproducts) = 6 × 413 + 1 × 347 = 2825 kJ
<em>For the system</em>
:
ΔHrxn = 2700 - 2825 = -125 kJ
Answer:
Hypsochromic compound, More polar solvent
Explanation:
Hypsochromic shift refers to the shift of solution colour to blue side of the visible spectrum (blueshift) with increasing polarity of the solvent. In our case, the solution changes to orange colour from red when solvent is changed. This means that the emission spectrum of the solution underwent blueshift. (As orange colour is on the 'blue' side for red colour.) So this is a hypsochromic shift, and the new solvent is more polar that the previous one, as it caused hypsochromic shift.
Answer:
Explanation:
Hello there!
In this case, according to the given information, it turns out possible for us to figure out the required net ionic equation by firstly writing out the complete molecular equation between aspirin and sodium acetate:
Whereas acetic acid and sodium acetylsalicylate are formed. Now, we write the complete ionic equation whereby sodium acetate and sodium acetylsalicylate are ionized because they are salts yet neither aspirin nor acetic acid are ionized as they are weak acids:
Finally, for the net ionic equation we cancel out the sodium spectator ions to obtain:
Regards!
It requires a force in the direction opposite to the motion of the object for it to slow down.
