Question

Calculate no. of atoms in 4.9 g of $H_{2}S{O}_4$.

• A. $24.2\times {10}^{23}$ atoms
• B. $21\times {10}^{23}$ atoms
• C. $2.1\times {10}^{23}$ atoms
• D. none of these

Answer 1

Answer: (C)

$2.1\times {10}^{23}$ atoms

No. of atoms in $4.9g$ of $H_2{SO}_4$

$1moleof{H}_2{SO}_4⟶6.022\times {10}^{23}atomsNo.ofmole=\frac{4.9}{98}=\frac{49}{98\times 10}=\frac{1}{20}=0.050.05moleof{H}_2{SO}_4⟶0.05\times 6.022\times {10}^{23}atoms⟶0.3011\times {10}^{23}molecules$

No. of atoms in $4.9g$ of $H_2{SO}_4=8\times 3.011\times {10}^{22}atoms=2.1\times {10}^{23}atoms$