Answer:
75603.86473 K
Explanation:
Given that:
The 1st excited electronic energy level of He atom = 3.13 × 10⁻¹⁸ J
The objective of this question is to estimate the temperature at which the ratio of the population will be 5.0 between the first excited state to the ground state.
The formula for estimating the ratio of population in 1st excited state to the ground state can be computed as:

From the above equation:
Δ E = energy difference = 3.13 × 10⁻¹⁸ J
k = Boltzmann constant = 1.38 × 10⁻²³ J/K

Thus:





T = 75603.86473 K
Moles = 4.03 x 10^21
------------------------
6.02 x 10^23
= 6.69 x 10^-3 moles.
Hope this helps!
The correct answer is B. Solubility describes the amount of solute that can be dissolved in a solvent. This value is not constant is affected by many factors. One factor is the temperature. An increase in temperature, a corresponding change in solubility also can be observed. The increase leads to a decrease in the solubility and the opposite. A decrease is observed since gas molecules are now has enough energy to escape the liquid phase and go to the gas phase.
The time required to reduce the concentration from 0.00757 M to 0.00180 M is equal to 1.52 × 10⁻⁴ s. The half-life period of the reaction is 9.98× 10⁻⁵s.
<h3>What is the rate of reaction?</h3>
The rate of reaction is described as the speed at which reactants are converted into products. A catalyst increases the rate of the reaction without going under any change in the chemical reaction.
Given the initial concentration of the reactant, C₀= 0.00757 M
The concentration of reactant after time t is C₁= 0.00180 M
The rate constant of the reaction, k = 37.9 M⁻¹s⁻¹
For the first-order reaction: 
0.00180 = 0.00757 - (37.9) t
t = 1.52 × 10⁻⁴ s
The half-life period of the reaction: 

Half-life of the reaction = 9.98 × 10⁻⁵s
Learn more about the rate of reaction, here:
brainly.com/question/13571877
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activation energy start off chemical reaction