Answer:
59.077 kJ/mol.
Explanation:
- From Arrhenius law: <em>K = Ae(-Ea/RT)</em>
where, K is the rate constant of the reaction.
A is the Arrhenius factor.
Ea is the activation energy.
R is the general gas constant.
T is the temperature.
- At different temperatures:
<em>ln(k₂/k₁) = Ea/R [(T₂-T₁)/(T₁T₂)]</em>
k₂ = 3k₁ , Ea = ??? J/mol, R = 8.314 J/mol.K, T₁ = 294.0 K, T₂ = 308.0 K.
ln(3k₁/k₁) = (Ea / 8.314 J/mol.K) [(308.0 K - 294.0 K) / (294.0 K x 308.0 K)]
∴ ln(3) = 1.859 x 10⁻⁵ Ea
∴ Ea = ln(3) / (1.859 x 10⁻⁵) = 59.077 kJ/mol.
It is a true fact that ionic crystals are excellent insulators and can hold a large amount of heat before melting or boiling. The correct option among the two options that are given in the question is the first option. Salt is a great example of ionic crystals and we know that it takes a huge amount of time to melt or boil.
Argon is a suitable choice for light bulbs because it is inert. Compared to a reactive gas like oxygen, the metal filimant would burn up in a reactive environment, which is why a noble gas is used.
Answer:
14,448 J of heat would it take to completely vaporize 172 g of this liquid at its boiling point.
Explanation:
The heat Q that is necessary to provide for a mass m of a certain substance to change phase is equal to Q = m*L, where L is called the latent heat of the substance and depends on the type of phase change.
During the evaporation process, a substance goes from a liquid to a gaseous state and needs to absorb a certain amount of heat from its immediate surroundings, which results in its cooling. The heat absorbed is called the heat of vaporization.
So, it is called "heat of vaporization", the energy required to change 1 gram of substance from a liquid state to a gaseous state at the boiling point.
In this case, being:
- L= 84
and replacing in the expression Q = m*L you get:
Q=172 g*84
Q=14,448 J
<u><em>14,448 J of heat would it take to completely vaporize 172 g of this liquid at its boiling point.</em></u>
Explanation:
Atoms can join together - they form bonds together - to make MOLECULES. ... For example, a hydrogen atom forms one bond, an oxygen atom forms two, and carbon forms four bonds. Look at that molecule of water again - each hydrogen has one bond, and the oxygen in the middle has two bonds. Molecules can be much bigger.
