Question

number of neutron in hundred gram of helium​

Answer 1

25x2x6.022x10^23

Explanation:

mole of he=100/4=25

25 mole of he contains 25x6.022x10^23 he atoms

every he atom contains 2 neutron

therefore no. of neutron=25x2x6.022x10^23

Answer 2

Solution :-

First of all we need to find out the number of moles of Helium in 100 grams

As we know that

▪️Molar mass of Helium = 4g

▪️Molecular mass of Helium = 4u

▪️One mole = $N_A$ No. of particles

▪️No. of atoms in one molecule of Helium = 2

So as we know that

$No. \: of \: moles = \dfrac{Given\: mass}{Molar\: Mass}$

So Numbers of moles

$= \dfrac{100}{4}$

$= 25 \: moles$

Now as No. of neutron is one per atom of Helium .

So there is two neutrons in one molecule of Helium

So there is $2\times N_A \times 25$ Neutrons in 25 moles of Helium

As $N_A = 6.022 \times 10^{23}$

So Numbers of neutrons

$= 2 \times 6.022 \times 10^{23} \times 25$

$= 50 \times 6.022 \times 10^{23}$

$= 301.1 \times 10^{23}$

$= 3.011 \times 10^{25}$

So there are 3.011 × 10²⁵ Neutrons in 100 grams of Helium