Question

Find the no of positive and negetive charges in a glass of water 500 g..?​

Answer 1

GiveN :-

• There's water weighing 500g .

To FinD :-

• The number of positive and negative charges in it .

SolutioN :-

We are given 500 grams of water and we need to find the number of protons (+ve) and electrons (-ve) . We know that water is formed by combining two hydrogen atoms along with one oxygen atom ( Covalent Bond ) . So in one Hydrogen atom there's 1 proton and 1 electron . Therefore in two H Atoms there will be 2 protons and electrons. Coming to Oxygen , there's 8 protons and 8 electrons . In total molecule there's 8+2 = 10 electrons and protons . Lets find out number of moles now .

$\sf:\implies\pink{n_{(moles)}=\dfrac{Weight\ in \ gram }{Molecular \ wt . }}\\\\\sf:\implies n =\dfrac{500g}{(2+16)g}\\\\\sf:\implies n =\dfrac{500g}{18g}\\\\\sf:\implies\boxed{\pink{\frak{ n_{(moles)}= 27.77 \ moles }}}$

Now we know that in one mole there is 6.022 * 10²³ particles . Therefore in 27.77 moles there will be 27.77 * 6.022 *10²³ = 167.23 * 10²³ particles.

Again we know that charge on one proton is +1.6 × 10-¹⁹ C and on an electron is -1.6 × 10-¹⁹ C .

• Therefore , the total +ve charge will be ,

$\sf\to n_{(proton)} \times n_{(Molecules)}\times Charge_{(on\ proton )} \\\\\sf\to (10 )(1.6\times 10^{-19}C)(167.23\times 10^{23} \\\\\sf\to 267.58 \times 10^{5} C \\\\\sf\to \boxed{\pink{ + \tt 2.67 \times 10^7 C }}$

Subsequently there will same amount of negative charge ( since molecule is neutral) . That's

$\sf\to \boxed{\pink{ \tt - 2.67 \times 10^7 C }}$