Question

A cup contains $250g$ of water. Find the total positive charge present in the cup of water.

• A. $1.34\times {10}^{7}C$
• B. $2.43\times {10}^{19}C$
• C. $2.43\times {10}^{7}C$
• D. $1.34\times {10}^{19}C$

Answer 1

Answer: (A)

Mass of water $=250g$

Molecular mass of water $=18g$

Number of molecules in $18g$ of water $==6.02\times {10}^{23}$

Number of moleucles in one cup of water $=\frac{250}{18}\times 6.02\times {10}^{23}$

Each molecule fo water contains two hydrogen atoms and one oxygen atom, i.e., 10 electrons and 10 protons.

$\therefore$ Total positive charge present in one cup of water

$=\frac{250}{18}\times 6.02\times {10}^{23}\times 10\times 1.6\times {10}^{-19}C=1.34\times {10}^{7}C$