Convert between mass, moles, and atoms of an element. How many Sn atoms are ther
ID: 479348 • Letter: C
Question
Convert between mass, moles, and atoms of an element. How many Sn atoms are there in a 25.5 gram sample of elemental Sn? The molar mass of a compound is the mass in grams of one mole of the compound. It is numerically eq formula (or molecular) weight. Formula weight is the sum of the atomic weights of the elements that multiplied by the number of atoms of each element in the formula for the substance. For substances tha molecules, the formula weight is called the molecular weight For example, one molecule of water,Explanation / Answer
Ans. Atomic mass of Sn = 118.71 g /mol
That is, 1 mole of Sn atoms weigh 118.71 g.
1 mole = 6.022 x 1023 atoms
Alternatively, 118.71 g (= 1 mole) Sn consists of 6.022 x 1023 atoms.
Now,
Number of moles of Sn in 25.5 g sample = Given mass of Sn / Atomic mass of Sn
= 25.5 g/ (118.71 g/ mol)
= 0.21481 mol
Number of Sn atoms in 0.21481 mol sample = Number of mole x Avogadro number
= 0.21481 mol x (6.022 x 1023 atoms/ mol)
= 1.29 x 1023 atoms
Therefore, 25.5 g (= 0.21481 mol) of Sn consists of 1.29 x 1023 atoms.