0.7 l of h2 enters a reaction at standard temperature and pressure.
how many particles of h2 reacted?
2.69 x 1022 particles h2
1.88 x 1022 particles h2
1.35 x 1025 particles h2
4.21 x 1023 particles h2

1.88 × 10²³ particles

Explanation:

Given data:

Volume of H₂ = 0.7 L

Number of particles at STP = ?

Solution:

First of all we will calculate the number of moles of H₂.

PV = nRT

n = PV / RT

n = 1 atm . 7 L / 0.0821 L. atm. mol⁻¹. k⁻¹ × 273.15 K

n = 7 atm. L / 22.43 L. atm. mol⁻¹

n = 0.312 mol

it is known that,

2 g H₂ = 1 mol = 6.022 × 10²³ particles

For 0.312 mol

              0.312 × 6.022 × 10²³ particles

                    1.88 × 10²³ particles