a 108ml sampl of gas has a mass of 77.96mg at a pressure of 1140mmhg and temperature of 183°c .what is the molar mass of the gas ?

Molar mass = 20 g/mol

Explanation:

Given data:

Volume of gas = 108 mL

Mass of gas = 77.96 mg (77.96/1000 = 0.08 g)

Pressure of gas = 1140 mmHg

Temperature of gas = 183°C

Molar mass of gas = ?

Solution:

First of all we will calculate the number of moles of gas.

PV = nRT

R = general gas constant = 0.0821 atm.L/ mol.K

Now we will convert the units and then we will put the values in formula.

Volume of gas = 108 mL× 1 L/1000 mL= 0.108 L

Pressure of gas = 1140 mmHg× 1 atm / 760 mmHg = 1.5 atm

Temperature of gas = 183+273 = 456 K

PV = nRT

1.5 atm ×0.108 L = n × 0.0821 atm.L/ mol.K ×456 K

0.162 atm.L =  n ×37.44 atm.L/ mol

n = 0.162 atm.L/37.44 atm.L/ mol

n = 0.004 mol

Molar mass of gas:

Number of moles = mass/molar mass

0.004 mol = 0.08 g / molar mass

Molar mass = 0.08 g /0.004 mol

Molar mass = 20 g/mol

a saline water is fed to a reverse osmosis unit at flow rate o rotameter connected to reject (retentate) line reads 8 installed in reject and permeate line reads 15.2 milli siemens/cm and 300 micro siemens/com respectively.

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.