12. O2 is present in 1 litre flask at a pressure of 1.52 x 103 mm of H

1.	12. O2 is present in 1 litre flask at a pressure of 1.52 x 103 mm of Hg. Calculate mass of O2 at0°C
Answer» NOTE THIS STEP :First we should calculate the number of moles of the gas under the given condition by the relationPV = nRT HereP= 7.6 * 10-10mm Hg = 7.6 10-10/760 atm. = 1 10-12atm. V= 1 litre T= 273 + 0 = 273K R= 0.082 litre atm./K/mol Putting the values in equation n=PV/RT= 1 10-121/0.082 273 moles now since 1 mole = 6.023 1023molecules 10-12/0.082 273 moles = 6.023 102310-12/0.082 273 molecules = 2.7 * 1010molecules

12. O2 is present in 1 litre flask at a pressure of 1.52 x 103 mm of Hg. Calculate mass of O2 at0°C

Answer»

NOTE THIS STEP :First we should calculate the number of moles of the gas under the given condition by the relationPV = nRT

HereP= 7.6 * 10-10mm Hg

= 7.6 *10-10/760 atm. = 1 * 10-12atm.

V= 1 litre

T= 273 + 0 = 273K

R= 0.082 litre atm./K/mol

Putting the values in equation

n=PV/RT= 1 *10-12*1/0.082 *273 moles

now since 1 mole = 6.023 * 1023molecules

10-12/0.082 *273 moles = 6.023 *1023*10-12/0.082 *273 molecules

= 2.7 * 1010molecules