Question

e
E. A student used a carbon pencil to write
his homework. The mass of this was
found to be 5 mg. With the help of this
calculate.
a. The number of moles of carbon in his
homework writing.
(Ans : 4.16 x 104)
P​

Answer 1

5 mg = 0.05 gm mole of carbon=given mass/atomic mass =0.05/12 = 0.004166666666

Answer 2

Answer:

The “number of moles” in 5 g of carbon $=4.16 \times 10^{4}$

To find:  

The no. of moles of carbon.

Solution:

The formula to calculate the “number of moles” when the ‘mass of the element’ is given

n = given weight of the element / molecular mass of the element,  

Where n is the ‘number of moles’

The molecular mass of Carbon is 12 g/mol

The given mass of Carbon is 5 mg = 0005 g

$\mathrm{N}=\frac{0.000 \mathrm{s}}{12}$

=0.0004166 or

$=4.16 \times 10^{4}.$