Question

How much positive and negative charge is there in a cup of water?Assume mass of 1 cup of water is 250g.

Answer 1

Hi ..


Assume that one cup holds 250 ml of water.

250 ml = 250 gram of water since its density is 1 in cgs.

number of moles of water in 250 gram = 250 / molar weight of water

n = 250/18 = 13.88 moles

1 mol has 6.022 x 1023 number of water molecules

So 250 g water will have 13.88 x 6.022 x 1023 number of H2O molecules

= 8.36 x 1024 number of molecules

One molecule of water has 2 hydrogen atoms (2 protons) and one oxygen atom (8 protons).

Total protons = 10 = total electrons (since it is neutral)

So 250 g water will have 10 x 8.36 x 1024 = 8.36 x 1025 protons.

charge of proton = 1.6 x 10-19 C

So total positive charge of 250 g water = 1.6 x 10-19 x 8.36 x 1025 = 13.37 x 106 C

which is equal to 13.3 MC (mega coulomb)

So one cup of water has 13.3 mega coulomb positive and negative charge, so that the overall charge is zero...


Hope this helps u!!

Answer 2

The positive and negative charge is there in a cup of water is 13.37 × 10^6.

Given:

1 cup of water is 250g.

To Find:

The positive and negative charge is there in a cup of water.

Solution:

To find the positive and negative charges is there in a cup of water we will follow the following steps:

As we know,

1 mole = 18g

Number of moles in 250g of water =

$\frac{250}{18} = 13.88$

1 mol of water has 6.022 x 1023 number of water molecules

So 13.88 moles of water will have 13.88 x 6.022 x 1023 number of H2O molecules = 8.36 x 1024 number of molecules

One molecule of water contains two hydrogen atoms and 1 oxygen atom.

Total protons = total electrons as the atom is neutral.

Number of electrons in hydrogen = 1

Number of electrons in oxygen = 8

The total number of electrons in the water molecule is 2×1 + 8 = 10.

Now,

1 mole has 10 electrons.

So, 13.88 moles of water will have 10 x 8.36 x 1024 = 8.36 x 10^25 protons.

Charge on one proton = 1.6 x 10-19 C

Charge on 8.36 x 10^25 the protons is 8.36 x 10^25 × 1.6 x 10-19 C = 13.37 × 10^6.

Charge on 8.36 x 10^25 the electrons is 8.36 x 10^25 × 1.6 x 10-19 C = 13.37 × 10^6.

Henceforth, the positive and negative charge is there in a cup of water is 13.37 × 10^6.