Question

How many atoms are present in $1kg$ of sugar?

• A. $7.92\times {10}^{25}$ atoms
• B. $6\times {10}^{23}$ atoms
• C. $6.022\times {10}^{25}$ atoms
• D. $1000$ atoms

Answer 1

The correct option is A $7.92\times {10}^{25}$ atoms

Mass of 1 mol or ($6.022\times {10}^{23}$ molecules) of $C_{12}{H}_{22}{O}_{11}=12\times 12+22\times 1+11\times 16=342g$

Number of molecules in $1000$ g $C_{12}{H}_{22}{O}_{11}=\frac{1000}{342}\times 6.022\times {10}^{23}=17.61\times {10}^{23}$

Number of atoms present in 1 molecule of $C_{12}{H}_{22}{O}_{11}=12+22+11=45$

Number of atoms in $1000$ g $C_{12}{H}_{22}{O}_{11}=45\times 17.61\times {10}^{23}$

$=792.45\times {10}^{23}=7.92\times {10}^{25}$ atoms