Question

calculate the number of molecules in 4 gram of Methane calculate the two moles of NH3​

Answer 1

Explanation:

number of molecules in 4 gm of methane

n=given mass/molar mass

= 4/16=0.25

Now No of molecules = n×Na (avagadro No.)

0.25×6.022×10^23

=1.5 × 10^23

hope it helps

Answer 2

Hey!

• Given, mass of Methane, CH4 = 4 grams.

: Now, calculate molecular mass of methane :

• Stochiometric coefficient of Carbon*Atomic mass + Stochiometric coefficient of Hydrogen*Atomic mass

• 1*12+4*1

• 12+4

• 16 u

: As you know, number of moles = mass/molecular mass :

• n = m/M

• n = 4/16 = 1/4 mole

: Now, number of molecules are :

• N = n*N`a (moles*Avogadro's number)

• N = 0.25*6.023*10²³

• N = 1.50575*10²³ molecules

: Mass of 2 moles of Ammonia, NH3 :

• Molecular mass = 1*14+3*1 = 17 u

• m = n*M

• m = 2*17 = 34 grams

: Molecules in 2 moles of Ammonia, NH3 :

• N = n*N`a

• N = 2*6.023*10²³ = 12.046*10²³ molecules

Hope it helps!