Question

Calculate the number of atoms of each type in 5.3g of $N{a}_{2}C{O}_3$?

• A. $0.1N_A$ atoms of Na, $0.05N_A$ atoms of Carbon, $0.15N_A$ atoms of Oxygen.
• B. $0.12N_A$ atoms of Na, $0.06N_A$ atoms of Carbon, $0.15N_A$ atoms of Oxygen.
• C. $0.15N_A$ atoms of Na, $0.06N_A$ atoms of Carbon, $0.15N_A$ atoms of Oxygen.
• D. $0.2N_A$ atoms of Na, $0.05N_A$ atoms of Carbon, $0.25N_A$ atoms of Oxygen.

Answer 1

The correct option is A

$0.1N_A$ atoms of Na, $0.05N_A$ atoms of Carbon, $0.15N_A$ atoms of Oxygen.

Molecular mass of $N{a}_{2}C{O}_3$ = $23\times 2+12+16\times 3$ = 106 g

106g of $N{a}_{2}C{O}_3\to$ 1 mole

5.3g of $N{a}_{2}C{O}_3\to \frac{5.3\times 1}{106}$ = 0.05 mole

1 mole of $N{a}_{2}C{O}_3$ have $2\times 6.022\times {10}^{23}$ atoms of Na, $1\times 6.022\times {10}^{23}$ atom of Carbon, $3\times 6.022\times {10}^{23}$ atoms of Oxygen.

0.05 mole of $N{a}_{2}C{O}_3$ have $0.05\times 2\times 6.022\times {10}^{23}$ atoms of Na, $0.05\times 6.022\times {10}^{23}$ atom of Carbon, $3\times 0.05\times 6.022\times {10}^{23}$ atoms of Oxygen.