Question

number of neutrons present in 4.5g of H2O​

Answer 1

Explanation:

Actually each molecule of water consists of H2O. H is just one proton and one electron. No neutrons. O is 8 protons, 8 neutrons, and 8 electrons.

Answer 2

Answer:

The total number of neutrons present in $4.5g$ of $H_{2}O$is $12\times 10^{23}$ neutrons.

Explanation:

Given,

The mass of $H_{2}O$ = $4.5g$

The total number of neutrons present in $4.5g$ of $H_{2}O$ =?

As we know,

• In one hydrogen,1 proton and 1 electron are present; there is no neutron.
• In oxygen, eight neutrons are present.

Therefore,

• One molecule of water contains = $8$ neutrons

Also,

• The molar mass of $H_{2}O$ = $18g/L$

Now,

• The number of moles of $H_{2}O$ = $\frac{Given mass}{Molar mass}$ = $\frac{4.5}{18}$ = $0.25mol$

As we know,

• $1 mole$ = $6.022 \times 10^{23}$ molecules
• $0.25 mole$ = $0.25\times 6.022 \times 10^{23}$ molecules = $1.5 \times 10^{23}$ molecules

Thus,

• The total number of neutrons present in $4.5g$ of $H_{2}O$ = Number of neutrons in one molecule of $H_{2}O$ × total number of molecules in $4.5g$ of $H_{2}O$​

Hence,

• The total number of neutrons present in $4.5g$ of $H_{2}O$ = $8\times 1.5 \times 10^{23}$ = $12\times 10^{23}$ neutrons.