3.42 g of sucrose is dissolved in 18g of water in a beaker. The number of oxygen atoms in the solution are

Question

I am not able to do this Q, and if possible please answer this without using the formulas but in the arithmetic way

Thank You!

Answer 1

The formula for sucrose is C₁₂H₂₂O₁₁

The molar mass sucrose = 342 g / mol

The formula for water is H₂O

The molar mass of water is 18 g/mol

So first, we'll find the MOLES of sucrose that we have:

3.42 g sucrose x 1 mol sucrose / 342 g = 0.01 moles of sucrose

Next we can find the number of moles of O in 0.01 moles of sucrose:

each mol sucrose has 11 moles of O, so 0.01 moles sucrose has 0.01 x 11 = 0.11 moles of O

Do the same for water:

moles of H₂O = 18 g H₂O x 1 mol H₂O / 18 g = 1 mol H₂O

How many moles of O is this? Each mol H2O has 1 mol O, so we have 1 mol O

Now we add the moles of O present and we get 0.11 mols O + 1 mol O = 1.11 moles O

To convert this to ATOMS of O we use Avogadro's number, 6.02x10²³ atoms / mole

1.11 moles O x 6.02x10²³ atoms of O / mole of O = 6.68x10²³ atoms of O

Answer 2

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 (a molecule of fructose and glucose; Sugar)



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

where N_A = 6.023×10²³

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

= 0.11× N_A atoms of oxygen

= 18 g/(1 × 2+ 16)gmol^-1

=18 g /18 gmol^-1

= 1mol

1mol of water (H₂O) contains 1 × N_A 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 N_A + 1.0 N_A = 1.11N_A

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