Question

Four grams of caustic soda contains :

(a) $6.02\times {10}^{23}atomsofit,$
(b) 4 g atom of sodium,
(c) $6.02\times {10}^{22}$ molecules

(d) 4 moles of NaOH.

Answer 1

Grams into moles:

$4gNaOH\times \frac{1molNaOH}{39.99g\left(molarmass\right)NaOH}=0.1molNaOH$

Then find the number of molecules using Avogadro's number:

$0.1molNaOH\times \frac{6.02\times {10}^{23}moleculesofNaOH}{1molNaOH}$

$=6.02\times {10}^{22}moleculesNaOH$


(c) $6.02\times {10}^{22}molecules$