Answer:
Explanation:
Temperature of air = 18°C = 273 + 18 = 291 K .
volume = 500 cc = 0 .5 litre .
pressure = one atmosphere ( atm) .
From gas equation , we can calculate this volume at NTP as follows.
volume = .5 x ( 273 / 291 ) litre
= 0.469 litre .
In any gas at NTP , 22.4 litre contains 6.02 x 10²³ molecules
.469 litre will contain 6.02 x 10²³ x .469 / 22.4 molecules
= 126 x 10²⁰ molecules .
b )
one mole = 6.02 x 10²³ molecules
6.02 x 10²³ molecules has weight of 28.96 grams
126 x 10²⁰ molecules has weight of 28.96 x 126 x 10²⁰ / 6.02 x 10²³ grams
= .606 gram .
c )
volume of all the air in the atmosphere = volume of sphere
= 4 / 3 x π x R³
= ( 4 / 3) x 3.14 x (999.5 x 10³ )³ m³
= 4.18 x 10¹⁸ m³
density of air = 1.225 kg / m³
mass of air = 1.225 x 4.18 x 10¹⁸ kg
= 5.12 x 10¹⁸ kg
d )
volume of air inhaled by 7 billion people
= . 5 x 7 x 10⁹ litre
= 3.5 x 10⁶ m³ .
Total volume of air in atmosphere = 4.18 x 10¹⁸ m³
required percentage
= 3.5 x 10⁶ x 100 / 4.18 x 10¹⁸
= .8373 x 10⁻¹⁰ % .
