Question

The number of water molecules present in a drop of water weighing $0.018g$ is:

• A. $6.023\times {10}^{26}$
• B. $6.023\times {10}^{23}$
• C. $6.023\times {10}^{19}$
• D. $6.023\times {10}^{20}$

Answer 1

Answer: (D)

$6.023\times {10}^{20}$

Number of moles $=\frac{0.018}{18}=0.001moles$

Number of molecules $=moles\times N_A=6.022\times {10}^{20}molecules$