Question

A sample of C12 H22 O11 that contains 72 grams of oxygen also contains how many grams of oxygen?

ans. 88g
please give the solution...

Answer 1

Given info : A sample of C₁₂H₂₂O₁₁ that contains 72g of carbon.

To find : The mass of oxygen present in the sample is ..

solution : mass of carbon = 72g

atomic mass of carbon = 12 g/mol

so no of moles of Carbon = 72g/12g/mol = 6 moles

we see, 12 moles of carbon are present in 1 mole of sugar sample (C₁₂H₂₂O₁₁).

∴ 6 moles of carbon are present in 1/12 × 6 = 0.5 mole of sugar sample (C₁₂H₂₂O₁₁).

also 11 moles of oxygen are present in 1 mole of C₁₂H₂₂O₁₁.

∴ 5.5 moles of oxygen will be present in 0.5 mole of C₁₂H₂₂O₁₁.

now mass of 5.5 moles oxygen = 5.5 moles × atomic mass of oxygen

= 5.5 × 16 = 88g

Therefore 88g of oxygen is present in the sample.

Answer 2

Given : A sample of C₁₂H₂₂O₁₁ that contains 72g of carbon.

To find : The mass of oxygen present in the sample  

Solution :

• Mass of carbon = 72 g

• Atomic mass of carbon = 12 g/mol

• So no of moles of Carbon = 72 / 12 = 6 moles

• We see, 12 moles of carbon are present in 1 mole of sugar sample (C₁₂H₂₂O₁₁).

• ∴ 6 moles of carbon are present in 1/12 × 6 = 0.5 mole of sugar sample      

                                                                                    (C₁₂H₂₂O₁₁).

• Also 11 moles of oxygen are present in 1 mole of C₁₂H₂₂O₁₁.

• ∴ 5.5 moles of oxygen will be present in 0.5 moles of C₁₂H₂₂O₁₁.

• Mass of 5.5 moles oxygen = 5.5 moles × atomic mass of oxygen

                                               = 5.5 × 16 = 88g

• Therefore 88g of oxygen is present in the sample.