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
<u>Answer:</u> In a chemical reaction, the total mass of the particles in the system stays the same
<u>Explanation:</u>
Law of conservation of mass states that mass can neither be created nor be destroyed but it can only be transformed from one form to another form.
This also means that total mass on the reactant side must be equal to the total mass on the product side in a chemical reaction.
Every balanced chemical reaction follows law of conservation of mass.
<u>For Example:</u> Formation of water molecule

Total mass on reactant side = ![[2(2\times 1)+(2\times 16)]=36g/mol](https://tex.z-dn.net/?f=%5B2%282%5Ctimes%201%29%2B%282%5Ctimes%2016%29%5D%3D36g%2Fmol)
Total mass on product side = ![[2((2\times 1)+16)]=36g/mol](https://tex.z-dn.net/?f=%5B2%28%282%5Ctimes%201%29%2B16%29%5D%3D36g%2Fmol)
Hence, in a chemical reaction, the total mass of the particles in the system stays the same
The smallest volume is 30 cm^3.
<span>we can find the number of moles of gas using the ideal gas law equation
PV = nRT
where P - pressure - 1.22 atm
V - volume - 0.245 L
n - number of moles
R - gas constant - 0.08206 L.atm/mol.K
T - temperature - 298 K
substituting the values in the equation
1.22 atm x 0.245 L = n x 0.08206 L.atm/mol.K x 298 K
n = 0.0122 mol
molar mass of compound = mass present / number of moles therefore molar mass = 0.465 g / 0.0122 mol = 38.1 g/mol
the answer is d) 38.0 g/mol </span>
Answer: Option (B) is the correct answer.
Explanation:
According to Le Chatelier's principle, any disturbance causes in an equilibrium reaction will shift the equilibrium in a direction that will oppose the change.
For example, 
When we increase the temperature then the reaction will shift in a direction where there will be decrease in temperature.
This, means that the reaction will shift in the backward direction.
Thus, we can conclude that if the reaction is at equilibrium and the temperature increases, the equilibrium will shift so that there is more nitrogen dioxide.