Question

Determine the thermochemical equation for the oxidation of one mole of sucrose by a biological system.   (That means write a balanced chemical equation AND its enthalpy of reaction.)

Is the reaction gaining or losing entropy, S? Prove your answer with a calculation.

Determine the energy generated by eating one serving of Jelly Bellies, NOT from the package calorie list, but by calculating based on the grams of sucrose per serving of Jelly Bellies.

Answer 1

The balanced formula for the oxidation of sucrose:

C12H22O11 + 12 O2 --> 12 CO2 + 11 H2O

This is a combustion reaction.

Combustion is essentially the mixing of a compound (usually a hydrocarbon or carbohydrate) with oxygen, producing carbon dioxide and water. Combustion reactions are endothermic. They release heat.

The heat content of the products is less than the heat content of the reactants (delta H is negative).

The molar mass of sucrose C12H22O11 is:

12*(12.01 amu ) + 22*( 1.01 amu ) + 11*( 16.00 amu) = 342.34 g/mol.

n = m / M = (5.00 g) / (342.34 g/mol)

n = 0.0146 mol

(0.0145 mol) (5.65 * 10^3 kJ / 1mol) = 82.5 kJ is released.

b)

One serving size of jelly bellies contains 25 g of carbohydrates, all of which are sugars.

One Jelly Belly jelly bean contains 4 calories, making a standard serving size of 25 pieces add up to 100 calories.

All Jelly Belly jelly beans vary in terms of the specific ingredients that give them their flavor, but all also share the same fundamental ingredients that make them a jelly bean: sugar i.e., mainly composed of sucrose, corn starch and glucose syrup.

Jelly beans contains 70% of sugar of which maximum is sucrose. It also contains other sugars such as fructose.