Calculate the number of molecules in 2 kg of sodium hydroxide
[At. wt. Na= 23, O = 16, H = 1]

Explanation

Molecular weight of NaOH = 23 + 16 + 1 = 40
`therefore` gram molecule ofNaOH = 40 g
gram molecule of substance contains
`6.023xx10^(23)` number of molecules
`40g` of NaOH contains `6.023 xx 10^(23)` no. of molecules
`therefore2000g` of NaOH contains
`=(6.023xx10^(23))/40x2000`
`=50xx6.023xx10^(23)`
2kg of NaOH contains `3.011 xx 10^(25)` number of molecules.