Question

The number of molecule at NTP in 1 ml of an
ideal gas will be
(a) 6x10 ^23
(b) 2.69 x 10 ^19
(c) 2.69 x 10 ^23
(d) None of these​

Answer 1

Answer: (a) $2.69\times 10^{19}$

Explanation:

NTP is defined as normal temperature and pressure where the value of temperature is 293 K and the value of pressure is 1 atm.

To calculate the moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given volume}}{\text{Molar volume}}$  

Given volume = 1 ml

Molar volume = 22.4 L = 22400 ml    (1L=1000ml)

Putting values in above equation, we get:

$\text{Moles}=\frac{1ml}{22400ml}=0.00004moles$

According to avogadro's law, 1 mole of every substance weighs equal to the molecular mass and contains avogadro's number $6.023\times 10^{23}$ of particles.

$C_2H_4(g)+3O_2(g)\rightarrow 2CO_2(g)+2H_2O(g)$

1 mole of an ideal gas contains=  $6.023\times 10^{23}$ molecules

Thus 0.00004 moles of an ideal gas contains =$\frac{6.023\times 10^{23}}{1}\times 0.00004=2.69\times 10^{19}$ molecules