Question

44.3.42 g of sucrose are dissolved in 18 g of water in a beaker. The numbers of oxygen atoms in the solution are: (a) 6.68 ×1023 (b) 6.09 ×1022 (c) 6.022 ×1023 (d) 6.022 ×1021​

Answer 1

Answer:

(a) 6.68 × 1023

Carbon = 12

Hydrogen = 1

Oxygen = 16

C = 12 × 12 = 144

H = 1 × 22 = 22

O = 16 × 11 = 176

Sucrose = 144 + 22 + 176 = 342 g/mol

1 mol of sucrose (C12H22O11) contains = 11× NA atoms of oxygen,

where NA = 6.023×1023

0.01 mol of sucrose (C12H22O11) contains = 0.01 × 11 × NA atoms of oxygen

= 0.11× NA atoms of oxygen

= 18 g/(1 × 2+ 16)gmol-1

=18 g /18 gmol-1

= 1mol

1mol of water (H2O) contains 1 × NA atom of oxygen

Total number of oxygen atoms = Number of oxygen atoms from sucrose + Number of oxygen atoms from water

Total number of oxygen atoms = 0.11 NA + 1.0 NA = 1.11NA

Number of oxygen atoms in solution = 1.11 × Avogadro’s number

Number of oxygen atoms in solution = 1.11 × 6.022 ×1023

Number of oxygen atoms in solution = 6.68 × 1023