1) How many molecules are there in 985 mL of nitrogen at 0.0° C and 1.00 x 10-6 mm Hg?

Answer : The number of molecules present in nitrogen gas are,

Explanation :

First we have to calculate the moles of nitrogen gas by using ideal gas equation.

where,

P = Pressure of gas =      (1 atm = 760 mmHg)

V = Volume of gas = 985 mL = 0.982 L    (1 L = 1000 mL)

n = number of moles  = ?

R = Gas constant =

T = Temperature of gas =

Now put all the given values in above equation, we get:

Now we have to calculate the number of molecules present in nitrogen gas.

As we know that 1 mole of substance contains number of molecules.

As, 1 mole of gas contains number of molecules

So, mole of gas contains number of molecules

Therefore, the number of molecules present in nitrogen gas are,

particle   p is an electron and particle q is a neutron