The bulk of the energy utilized by marathon runners is provided by .

a. glycogen

b. fatty acids

c. blood glucose

d. protein

C

Explanation:

Glucose is the molecule that instantly supplies energy. The metabolism of carbohydrates ends in the production of glucose which is released directly into the blood stream to supply energy for physical activity.

answer : third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

explanation :

let us write down the given equations

equation 1 :

equation 2 :

equation 3 :

let us use hess's law to find out which 2 equations can be added to get the third equation.

let us reverse equation 2 and multiply it by 2. the new equation that we get is,

equation 4 :

let us add equation 1 & 4

the above equation is similar to equation 3 but has different value for dhrxn.

therefore third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

c. orbital shape i hope this is correct