Question

Calculate the number of moles in:
i) 12.046 x 1023 atoms of Copper ii) 27.95g of Iron
iii) 1.51 x 1023 molecules of CO2

TNSCERT Class 10 Chemistry Ch 10 Atoms and Molecules

Answer 1

i)
=> 1 mole of Cu has 6.023 x1023 atoms
=> (?) moles of Cu has 12.046 x 1023 atoms
{by cross multiplication}
=> 12.046 x 1023/ 6.023 x 1023
=> 2 moles......Ans
ii)
=>1 mole of Fe weighs 56 grams
=>(?) moles of Fe will weigh 27.95 grams
{by cross multiplication}
=> 27.95 x 1/ 56
=>0.499 moles or 0.5 moles.....Ans
iii)
1 mole of Co2 has =>6.023 x 1023 molecules
=> (?) moles of Co2 will have 1.51 x 1023 molecules
{by cross multiplication}
=> 1.51 1023x 1/ 6.023 x 1023
=> 0.25 moles.....Ans

Answer 2

Answer:

i)

=> 1 mole of Cu has 6.023 x1023 atoms

=> (?) moles of Cu has 12.046 x 1023 atoms

{by cross multiplication}

=> 12.046 x 1023/ 6.023 x 1023

=> 2 moles......Ans

ii)

=>1 mole of Fe weighs 56 grams

=>(?) moles of Fe will weigh 27.95 grams

{by cross multiplication}

=> 27.95 x 1/ 56

=>0.499 moles or 0.5 moles.....Ans

iii)

1 mole of Co2 has =>6.023 x 1023 molecules

=> (?) moles of Co2 will have 1.51 x 1023 molecules

{by cross multiplication}

=> 1.51 1023x 1/ 6.023 x 1023

=> 0.25 moles.....Ans