Question

How many particles of Na are there in 1.43g of a molecular compound with a Molar mass of 23g?

Answer 1

Answer:

3.74 x 10²² particles

Explanation:

Given parameters:

Mass of compound  = 1.43g

Molar mass of compound  = 23g

Unknown:

Number of particles of sodium = ?

Solution:

To find the number of particles of Na in the compound, we need to obtain the mass of sodium from the total mass given;

          Mass of sodium  = $\frac{molar mass of Na}{molar mass of compound} x mass of sample$

                                      = $\frac{23}{23} x 1.43g$

                                       = 1.43g

Now find the number of moles of this amount of Na in the sample;

          Number of moles  = $\frac{mass}{molar mass}$ = $\frac{1.43}{23}$  = 0.062mole

Now;

                    1 mole of substance  = 6.02 x 10²³ particles

                       0.062 mole of substance  =  0.062 x 6.02 x 10²³ particles

                                                                     = 3.74 x 10²² particles