Consider the reaction: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O and ΔH = -2800 kJ. How many kJ of energy are released when 18 grams of glucose are combusted?

-616 kilo joules of energy is released when 40 grams glucose are combusted.

Explanation:

Balance equation of the reaction:

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O and ΔH = -2800 kJ

1 mole glucose undergoes combustion to release 2800 kJ of energy

atomic mass of 1 mole of glucose = 180.15 gram/mole

40 grams of glucose will have

number of moles =

number of moles =

                            = 0.22 moles of glucose in 40 gram.

1 mole of glucose when undergoes combustion yields -2800 kilo joules of energy

0.22 moles of glucose when undergoes combustion yields

=

x = -616 kilo joules of energy is released when 40 grams glucose undergoes combustion. (minus sign indicates release of energy)

answer: - 3.) the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.

solution: - as per the rules, oxidation number of oxygen in its compounds is -2. the sum of oxidation numbers of all the elements of a molecule or compound is zero.

also, the oxidation number in elemental form is zero.

in no, the oxidation number of o is -2 so the oxidation number of n is +2 so that the sum is zero.

similarly, the oxidation number of c in co is +2 and o is -2.

on product side the oxidation number of n is 0 as it is in the elemental form() .

oxidation number of c in carbon dioxide is +4 as there are two oxygen in it and we know that each oxygen is -2.

so, oxidation number of n is changing from +2 to 0 and the oxidation number of c is changing from +2 to +4.

since nitrogen is reduced and hence no is acting as an oxidizing agent. carbon is oxidized and so co is acting as a reducing agent.

so, the right choice is number 3.)the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.

what does the table look like