Using incorrect concentrations. If your vitamin C standard solution is too concentrated or your iodine titration solution is too diluted, or your starch indicator solution is not between 0.5 to 1.0%, it may require much more than 50 mL of iodine solution to titrate the standard solution and/or orange juice.
The following summarizes some common causes of fatigue but is not meant to be comprehensive: Metabolic/endocrine: anemia; hypothyroidism; diabetes; electrolyte abnormalities; kidney disease; liver disease; Cushing's disease.
A stressful emotional situation may also cause fatigue. This type of fatigue usually clears up when the stress is relieved. Many prescription and nonprescription medicines can cause weakness or fatigue. The use or abuse of alcohol, caffeine, or illegal drugs can cause fatigue.