Question

The number of molecules in $35.5$ g of chlorine gas is:

• A. $3.011\times {10}^{23}$
• B. $6.022\times {10}^{23}$
• C. $9.033\times {10}^{23}$
• D. $1.2044\times {10}^{24}$

Answer 1

Answer: (A)

$3.011\times {10}^{23}$

Cl atom =35.5g per mole

hence, $C{l}_2$ = 71g per mole

but as its given how many molecules in 35.5g of $C{l}_2$ ?

35.5g of $C{l}_2$ = 0.5 mole

every mole of chlorine contains Avogadro's number =$6.022\times {10}^{23}$

therefore no. of molecules in 0.5 mole of chlorine = $6.022\times {10}^{23}\times 0.5$

= $3.011\times {10}^{23}$