Every cell is surrounded by a thin membrane. What is the main function of this cell membrane? A. to protect the cell from invasion by bacteria and viruses
B.
to allow each cell to form connections with other cells
C.
to limit the size of the cell and keep the shape of the cell the same
D.
to separate the inside of the cell from the outside environment

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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 .

The molar mass of iron(fe) is 55.8 g/mol. what is the mass in grams of 2.25 moles of iron?