Portland cement concrete (PCC) has a density of 150 lb/ft3. How many kilograms of PCC are required to cast a cylindrical column 1.15 m in diameter and 7.8 m in height? (1 kg = 2.205 lb, 1 inch = 2.54 cm)

An animal cell loses the ability to convert energy stored in food to energy that the cell can use. which of the cell's organelles has stopped working? a. the mitochondria b. the nucleus c. the vacuoles d. the endoplasmic reticulum

Nitric acid can be formed in two steps from the atmospheric gases nitrogen and oxygen, plus hydrogen prepared by reforming natural gas. in the first step, nitrogen and hydrogen react to form ammonia: (g) (g) (g) in the second step, ammonia and oxygen react to form nitric acid and water: (g) (g) (g) (g) calculate the net change in enthalpy for the formation of one mole of nitric acid from nitrogen, hydrogen and oxygen from these reactions. round your answer to the nearest .

Introduction of drugs into the gastrointestinal tract is a form of administration. a. enteral b. topical c. parenteral d. inhalation