Answer:
The 12L helium tank pressurized to 160 atm will fill <em>636 </em>3-liter balloons
Explanation:
It is possible to answer this question using Boyle's law:

Where P₁ is the pressure of the tank (160atm), V₁ is the volume of the tank (12L), P₂ is the pressure of the balloons (1atm, atmospheric pressure) And V₂ is the volume this gas will occupy at 1 atm, thus:
160atm×12L = 1atm×V₂
V₂ = 1920L
As the tank will never be empty, the volume of the gas able to fill balloons is the total volume minus 12L, thus the volume of helium able to fill balloons is:
1920L - 12L = 1908L
1908L will fill:
1908L×
= <em>636 balloons</em>
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I hope it helps!
Molecular weight of vanillin = 152 g/mol
Futher molecular formula of vanillin is C8H8O3
Atomic weight of oxygen = 16 g/mol
Thus, 152 g of vanillin contains 16 g of oxygen
∴ 0.045 g (45 mg) of vanillin contains

= 0.00473 g
Also, number of moles of vanillin in 0.045 g sample =

Now, 1 mole = 6.023 X 10^23 molecules
∴ 2.96 X 10^-4 mole = 1.78 X 10^20 molecules
From molecular formula, it can be seen that 1 molecule of vanallin contain 3 atoms of oxygen
∴1.78 X 10^20 molecules contain 3 X 1.78 X 10^20 = 5.34 X 10^20 oxygen atoms
The correct answer is Na > K > Rb.
The order predicted would be ionization energy of sodium is greater than the ionization energy of potassium, which is greater than the ionization energy of rubidium.
The ionization energy refers to energy, which has to be supplemented to a gaseous atom in order to withdraw an electron and produce a positive ion. The ionization energy decreases in going down a group. The cause of the decline of the ionization energy down a group is that as one moves down a group, the size of the atom increases that signifies that the valence electrons get further away from the nucleus, and thus, less energy is required to withdraw the electrons.
It was Erwin Schrodinger.