A piece of sodium weights 0.023 gram the number of atoms present in it are

Calculate mass of sodium which contains same number of atoms as are present in 4 g of calcium (Atomic weight Na = 23 , atomic weight Ca = 40 )

The number of gram-atoms in 8 g of He are

A compound has 40% of carbon by weight. If molecular weight of the compound is 90, the number of carbon atoms present in 1 molecule of the compound are

If the atomic mass of sodium is 23 , the number of moles in 46gm of sodium is:

The atomic mass of aluminum is 27. The number of moles present in 81 grams of aluminum is ______