Question

question 5, 6

5. (10 pts) Helena compares oxidation with reduction. Match each term with the correct definition a) Oxidation • Gain of oxygen • Gain of hydrogen b) Reduction • Loss of electron • Decrease in oxidation number • Gain of electron 6. Jasmine finds that the carbohydrate is one of the major sources of energy of our body. The combustion of the carbohydrate glucose produces carbon dioxide and water: C6H12O6 + O2 CO2 + H2O (unbalanced) a) (2 pts) Balance this equation. b) (3 pts) If he burns 10 moles of glucose, how many moles of carbon dioxide would be produced? c) (5 pts) If he burns 360 g of glucose, how many grams of oxygen is needed?

Answer 1

Ans 5 :

Oxidation and reduction are the two chemical processes that increase or decrease the oxidation number of the element.

This happens by loosing or gaining electrons.

So here :

a) Oxidation : Loss of electron

b) Reduction : Gain of electron

Ans 6 :

a)

The balanced equation is given as :

C₆H₁₂O₆ + 6O₂ = 6CO₂ + 6H₂O

b)

Each mol glucose makes 6 mol CO2

so 10 mol glucose will make :

= 6 x 10 mol

= 60 mol carbon dioxide

c)

Mol glucose = mass / molar mass

= 360 g / 180 g/mol = 2 mol

Each mol glucose needs 6 mol oxygen

so 2 mol glucose will need : 2 x 6 mol = 12 mol oxygen

mass of oxygen = mol x molar mass

= 12 mol x 32 g/mol

= 528 g oxygen