Answer:- 335 kcal of heat energy is produced.
Solution:- The balanced equation for the combustion of glucose in presence of oxygen to give carbon dioxide and water is:

From given info, 2803 kJ of heat is released bu the combustion of 1 mol of glucose. We need to calculate the energy produced when 3.00 moles of oxygen react with excess of glucose.
We could solve this using dimensional analysis as:

= 1401.5 kJ
Now, let's convert kJ to kcal.
We know that, 1kcal = 4.184kJ
So, 
= 335 kcal
Hence, 335 kcal of heat energy is produced by the use of 3.00 moles of oxygen gas.
Answer:
Option B
Explanation:
- For Option A the state is not changing but just has different look now.
- For Option B the state is changing from gas to liquid drops due to cold glass
- For Option C it hasn't changed state as both corn and flower is solid
- For Option D paper and ash are both solids
Therefore our answer must be Option B
I think it’s oxygen and carbon