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
B because....................
Answer:
Observe: To model how hydrogen and oxygen react to make water, type “H2+O2” into the Reactants box and “H2O” into the Products box.
As the equation is written, which element is not in balanced?
oxygen isn't balanced...
Explanation:
in reactants there is 2hydrogens and 2 oxygen
but in product there is balanced no if hydrogen bt there is only one no of oxygen
Explanation:
- It is known that the amount of heat necessary to raise the temperature of 1 gram of a substance by
is known as specific heat.
Since, q = 
So, larger is the specific heat of a substance less will be the change in its temperature.
Therefore, olive oil has less specific heat as compared to water. This means that olive oil would get hotter.
- Similarly, the specific heat of gold is lesser than the given materials or metals. Hence, gold will requires less heat to rise its temperature.
As a result, water present in gold will heat readily.
- As the relation between heat and specific heat is as follows.
q =
Therefore, calculate the amount of heat required by the water as follows.
q =
= 
= 33440 J
or, = 33.44 kJ (as 1 kJ = 1000 J)
Thus, 33.44 kJ heat would it take to raise the temperature of 100.0 g of water from 
to 
.
