Question

The total no.of protons in 36ml of water at 4°c

Answer 1

Given, volume of water = 36ml and density of water at 4°C = 1g/ml
so, mass of water = 36 × 1 = 36g
Mole of water = mass/molar mass
= 36g/18g/mol = 2 mol
∴ number of water molecule = mole of water × Avogadro's number
= 2 × 6.023 × 10²³
= 1.2046 × 10²⁴

We know, there are 10 protons in a molecule of water .
e.g., 8 protons of Oxygen atom and 2 protons of each two hydrogen atoms.
Now, number of protons = number of water molecule × 10
= 1.2046 × 10²⁴ × 10
= 1.2046 × 10²⁵

Hence, answer is 1.2046 × 10²⁵

Answer 2

density = 1gm/ml

volume = 36 ml

mass = density * volume

= 1gm/ml * 36 ml

= 36gm

No. of moles of water

= given mass / molar mass

= 36gm/18gm/mole

= 2moles

no. of water molecules

= 2* avogadro's no.(Na=6.022*10^23)

= 2Na

total protons=2Na*protons of H2O(i.e.,10)

therefore, 2Na*10

=20Na