Answer:
1.63425 × 10^- 18 Joules.
Explanation:
We are able to solve this kind of problem, all thanks to Bohr's Model atom. With the model we can calculate the energy required to move the electron of the hydrogen atom from the 1s to the 2s orbital.
We will be using the formula in the equation (1) below;
Energy, E(n) = - Z^2 × R(H) × [1/n^2]. -------------------------------------------------(1).
Where R(H) is the Rydberg's constant having a value of 2.179 × 10^-18 Joules and Z is the atomic number= 1 for hydrogen.
Since the Electrons moved in the hydrogen atom from the 1s to the 2s orbital,then we have;
∆E= - R(H) × [1/nf^2 - 1/ni^2 ].
Where nf = 2 = final level= higher orbital, ni= initial level= lower orbital.
Therefore, ∆E= - 2.179 × 10^-18 Joules× [ 1/2^2 - 1/1^2].
= -2.179 × 10^-18 Joules × (0.25 - 1).
= - 2.179 × 10^-18 × (- 0.75).
= 1.63425 × 10^- 18 Joules.
D = 0.2 g / ml = 0.2 g / cm³
For example, density of steel is 7.85 g / cm³.
Density of pure water is 1.0 g/cm³. An object which has a density < 1.0 g/cm³ will float in water.
Answer: Material that has a density of 0.2 g/ml ( 0.2 g/cm³ ) is good for making couch cushions.
B. sublimation is the answer.
<u>Given:</u>
Volume of air inhaled V = 0.56 L
Temperature T = 37 C = 37 +273 = 310 K
Pressure P = 744 mmHg = 744/760 = 0.979 atm
% N2 in air = 78%
<u>To determine:</u>
The moles of N2 inhaled in one breath
<u>Explanation:</u>
Step 1: Calculate the moles of air inhales
Based on the ideal gas law:
PV = nRT
where P = pressure, T = temperature, V = volume, n = # moles
R = gas constant = 0.0821 L atm/mol-K
n = PV/RT = 0.979 * 0.56/0.0821*310 = 0.0215 moles of air
Step 2: Calculate the moles of N2
It is given that air contains 78% N2
Therefore:
moles of N2 = 0.0215 * 78/100 = 0.0168 moles
Ans: moles of N2 = 0.0168
