I think it is 11% I read it on a article on msn.
1.0 mole ---------- 6.02x10²³ molecules
4.5 moles -------- ?
4.5 * 6,02x10²³ / 1.0
= 2.709x10²⁴ molecules units
Answer:
the mass of the air in the room is 4.96512 kg ( in 0°C)
The 3 indicates the third electron shell. (Which has only 1 electron in it in this configuration)
Hope this helps! :)
Answer: Total pressure inside of a vessel is 0.908 atm
Explanation:
According to Dalton's law, the total pressure is the sum of individual partial pressures. exerted by each gas alone.

= partial pressure of nitrogen = 0.256 atm
= partial pressure of helium = 203 mm Hg = 0.267 atm (760mmHg=1atm)
= partial pressure of hydrogen =39.0 kPa = 0.385 atm (1kPa=0.00987 atm)
Thus 
=0.256atm+0.267atm+0.385atm =0.908atm
Thus total pressure (in atm) inside of a vessel is 0.908