Question

​calculate the no. of atoms in 1) 0.5 mole atoms of carbon 12, (2) 18g of glucose (3) 0.20 mole molecules of oxygen?

Answer 1

No.of atoms in 0.5 moles of C=3.011×10²³
No.of atoms in 18g  of C₆H₁₂o₆=0.732×10²³
No.of atoms in 0.20 mole molecules of oxygen=0.12046×10²³

Answer 2

0.5 mole atoms of carbon 12 contains $\bold{3.011 \times 10^{23}}$ atoms.

18 g of glucose contains $\bold{1.45 \times 10^{23}}$  mole of glucose.

0.20 mole atoms of oxygen contains $\bold{2.41 \times 10^{23}}$  atoms.

Solution:

1) 0.5 mole atoms of carbon 12

1 mole carbon atoms = $6.023 \times 10^{23}$ atoms

0.5 moles of carbon atoms = $0.5 \times 6.023 \times 10^{23}$ atoms

                                      $=3.011 \times 10^{23}$

2) 18g of glucose

Molar mass of Glucose = 180 g/mol

$\frac{180 \mathrm{g}}{\text { mole }}=1\ mole\ of\ glucose$

18 g of glucose= $\left(\frac{18}{180}\right) \times 24 \times 18=1.45 \times 10^{23}mole\ of\ glucose$

3)  0.20 mole atoms of oxygen

1 mole oxygen atoms = $6.023 \times 10^{23}$  atoms

0.20 moles of oxygen atoms=$0.20 \times 2 \times 6.023 \times 10^{23} atoms=2.41 \times 10^{23} atoms$