What is the symbol of the amount of substance’s S.I. unit?

Which of the given reactions are counted as balanced reactions?

A piece of iron is 5 inches long. How much would it be in centimeters?

In a container, there are 4 moles of nitrogen, 3 moles of oxygen and 7 moles of hydrogen; find out the mole fraction of …

Which of the following may be an incorrect statement?

How many significant figures does 0.057 have?

What is the mass of hydrogen in terms of amu?

Which of the following is an empirical formula?