Question

calculate the number of particles in
(a) 46 g of Na atom
(b) 8 g of O2 moles
(c) 0.1 moles of carbon atom

Answer 1

hey...

1. no. of particles/atoms / molecules/ions.

=(given mass / molarmass)×avogadro's number.

=46/23× 6.022 ×10^23

=12.044 × 10^23.

2. N = m/M × avo.no. (molar mass of oxygen = 32)

= 8/32× 6.022× 10^23

= 1.51 × 10^23.


3. no. of particles = no of moles × avogadro's no.

= 6.022× 10^23 × 0.1

= 6.022 × 10^22.

Answer 2

Hey

Remember one thing that GMW means 1 mole which will be having
$6 \times {10}^{23}$
molecules



A)GMW of sodium is 23

we are asked to calculate weight of 46 grams..means there will
$12 \times {10}^{23}$
particles

B)GMW of Oxygen atom is 16
so, GMW of Oxygen molecule(O2) will be 32

So, 8gms of O2 contains
$1.5 \times {10}^{23}$
molecules.

C) as 1 mole contains
$6 \times {10}^{23}$
molecules/atoms,
by simple cross multiplication you can find that 0.1 mole of carbon has
$6 \times {10}^{22}$
atoms.


HOPE THIS HELPS YOU.