Question

Number of moles of neutron in 18g of H2O

a) 10
b) 4
c) 8
d) 5

Answer 1

4.81x10^24 (approx)..

Explanation:

according to question : 18g or 18ml of H20

{formula ~ no. of moles =mass / molecular mass }

1 mole = 6.023x10^23 atoms

H2 contains 0 neutron, O2 contains 8 neutrons in 1 atom of water

hence,

8 x 6.023 x 20^23

48.18 x 10^23

4.81 x 20^24

......... ...... ....... ........... .........

Answer 2

Answer: The correct answer is Option c.

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Mass of water = 18 g

Molar mass of water = 18 g/mol

Putting values in above equation, we get:

$\text{Number of moles of water}=\frac{18g}{18g/mol}=1mol$

To calculate the number of neutrons in water, we calculate the number of neutrons in each of the element.

Number of neutrons in Hydrogen = 0

Number of neutrons in Oxygen = 8

Number of neutrons that are present in 1 mole of water = $[(2\times 0)+8]=8$

In 1 mole of water, there are 8 neutrons present.

Hence, the correct answer is Option c.