Question

Find number of atom in [4] (i) 5.6 L of Hydrogen at NTP (ii) 2.2 g of CO

Answer 1

your question is ---> Find number of atom in (i) 5.6 L of Hydrogen at NTP (ii) 2.2 g of CO2.

(i) 5.6 L of Hydrogen at NTP,

we know, at normal temperature and pressure ( or NTP)

volume of 1 mole of substance = 22.4L

so, number of mole of hydrogen = 5.6/22.4L = 1/4 = 0.25 mol

now, number of hydrogen atom = number of mole of hydrogen × Avogadro's number

= 0.25 × 6.023 × 10²³

= 1.50575 × 10²³

(ii) 2.2g of CO2

molar mass of CO = 12 + 32 = 44g/mol

so, number of mole of CO2 = 2.2/44

= 1/20 = 0.05mol

now, number of CO molecule = number of mole of CO × Avogadro's number

= 0.05 × 6.023 × 10²³

= 3.0115 × 10²²

but one CO2 have three number of atoms ( one C and two O )

then, number of atoms = 3 × 3.0115 × 10²²

= 9.0345 × 10²²