help with chem please

Question

While working for a food science company, you need to analyze the energy content of a sugar substitute with the molecular formula C5H12O5.C5⁢H12⁢O5. As part of this process, you conduct a series of bomb calorimetry experiments. In each experiment, you place a sample of the sweetener in the calorimeter, and then measure the temperature change when the sweetener undergoes combustion. The heat capacity of the calorimeter is 4.371 kJ/ ∘C.4.371 kJ/ ∘C.

Write the balanced equation for the combustion of this compound.

Answer 1

Hi Margaret, looks like you are working on an interesting experiment/question packet! This question is asking for the balanced equation for the combustion of a sweetener molecule with formula C₅H₁₂O₅.

Combustion reactions follow the same reaction type as follows:

Hydrocarbon (C_xH_x) + O₂ ------> CO₂ + H₂O

We will change out the generic hydrocarbon formula for the one provided in this experiment scenario.

C₅H₁₂O₅ + O₂ ------> CO₂ + H₂O

Now, begin balancing by placing coefficients in front of your molecules. I recommend leaving the H and O for last when balancing, so let's start with the Carbons. There are 5 Carbons on the left, but only 1 on the right, so let's place a coefficient of 5 in front of the CO₂

C₅H₁₂O₅ + O₂ ------> 5 CO₂ + H₂O

Now that the Carbons are balanced with 5 on both sides, let's move on to the Hydrogens. There are 12 on the left, but only 2 on the right, so place a coefficient of 6 in front of the H₂O.

C₅H₁₂O₅ + O₂ ------> 5 CO₂ + 6 H₂O

Now let's look at the Oxygen last. There are 16 on the right side and 7 on the left side. Notice how O is present in both reactants on the left side of the reaction. We want to put a coefficient in front of the O₂ rather than the sugar molecule, otherwise it will throw off our C and H balancing. Let's do this by putting a coefficient of 5.5 or 11/2 in front of the O₂ to balance.

C₅H₁₂O₅ + 11/2 O₂ ------> 5 CO₂ + 6 H₂O

Mathematically this is balanced, but in Chemistry we want to have whole numbers as our coefficients. The 11/2 coefficient can be turned into a whole number by multiplying the entire equation by 2. If we double everything, than the 11/2 would become 11; 5 becomes 10; and 6 becomes 12. We will also double the one sugar molecule as well.

2 C₅H₁₂O₅ + 11 O₂ ------> 10 CO₂ + 12 H₂O

Please feel free to comment with any additional questions you may have with this problem. Thanks!