Answer:
The chemist can either:
a. Use a small fractionation apparatus.
b. Add a compound with a much higher boiling point.
Explanation:
Using a smaller fractionation apparatus or Vigreux column will help to minimize loss of the distillate.
If a compound with a higher boiling point is added, the vapors of this liquid will displace the vapors of this small amount of compound with a lower boiling point. This compound with a higher boiling point is known as a Chaser.
Answer:
![K=\frac{[CaO][CH_{4}][H_{2}O ]^{2} }{[CaCO_{2}][H_{2}]^4 }](https://tex.z-dn.net/?f=K%3D%5Cfrac%7B%5BCaO%5D%5BCH_%7B4%7D%5D%5BH_%7B2%7DO%20%5D%5E%7B2%7D%20%20%7D%7B%5BCaCO_%7B2%7D%5D%5BH_%7B2%7D%5D%5E4%20%20%7D)
Explanation:
The equilibrium expression is the K value equal to the product of the concentrations of the products over the product of the concentrations of the reactants. If there is a coefficient in front of the compound, raise the molecule to that power.
Since K is big, more product is expected. This is because of mathematic principles. A large numerator with a small denominator will produce a large number.
Alpha particle is equivalent to B. Helium atom (2 protons, 2 neutrons)
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
