Question

A student used a carbon pencil to write his homework. The Mass of this was found to be 5mg .with the help of this calculate.a.the no.of carbon in his homework writing.b.the no
of carbon atoms in 12mg of his homework writing​

Answer 1

Answer:

a) 6.022×10^18 b) 6.022×10^20

Answer 2

Hello Dear,

◆ Answer -

(1) In 5 mg, No of C-atoms = 2.51×10^20 atoms

(2) In 12 mg, No of C-atoms = 6.022×10^20 atoms

◆ Explaination -

(1) For 5 mg of homework writing -

No of C-atoms in 5 mg of homework -

N1 = n1 × NA

N1 = W1 / M × NA

N1 = 5×10^-3 / 12 × 6.022×10^23

N1 = 2.51×10^20 atoms

(2) For 12 mg of homework writing -

No of C-atoms in 12 mg of homework -

N2 = n2 × NA

N2 = W2 / M × NA

N2 = 12×10^-3 / 12 × 6.022×10^23

N2 = 6.022×10^20 atoms

Hope this helps you...