Question

3.42 grams of sucrose (C₁₂H₂₂O₁₁) are dissolved in 18 grams of water in a beaker. Find the number of atoms in the solution .
PEASE FAST IT'S CRITICAL

Answer 1

Number of moles of sucrose = mass / molar mass
= 3.42 / 342 (Molar mass of sucrose = 342 g mol^-1)
= 0.01 moles
Number of moles of water = 18 / 18
= 1 mole
0.01 moles of sucrose contain 6.022 X 10²³ or N_A (avogadro's number) molecules of sucrose and 1 mole of water contains N_A molecules of water.
0.01 mole of sucrose contains
Number of Carbon atoms = 0.01 X 12 N_A
Number of Hydrogen atoms = 0.01 X 22 N_A
Number of Oxygen atoms = 0.01 X 11 N_A
1 mole of water contains
Number of Hydrogen atoms =1 X 2 N_A
Number of Oxygen atoms = 1 X 1 X N_A
Total number of atoms in solution = (0.12 + 0.22 + 0.11 + 2 + 1) N_A
= 3.45 N_A