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.
Other medical causes of fatigue are the side effect of drugs, thyroid dysfunction, high calcium levels, rheumatologic illnesses, adrenal, kidney or liver problems. Some infections such as tuberculosis or hepatitis can cause fatigue, and indeed, fatigue can be their only symptom. Depression is also a major cause of fatigue. While unusual, uncontrolled diabetes can be the cause of fatigue. These patients generally also have other symptoms of diabetes such as excess thirst, frequent urination and blurred vision. Some drugs used to treat diabetes can cause fatigue by causing anemia or a metabolic change known as lactic acidosis.