Question

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

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

Answer 1

Answer: (B)

Mass of water $=250g$,
Molecular mass of water $=18g$
Number of molecules in 18 g of water $=6.02\times 10^{23}$
Number of molecules in one cup of water $=\frac{250}{18}\times 6.02\times 10^{23}$
Each molecule of 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
$=\frac{250}{18}\times 6.02\times 10^{23}\times 10\times 1.6\times 10^{-19}C=1.34\times 10^{7}C$