Calculate the number of moles in 15 atoms

The total mass of the 15 atoms above is
2.09 ×10−21 g . Calculate the mass, in grams, of one atom.

Calculate the molar mass of the atoms above and, using the periodic table, identify the element.

Calculate the mass of 5.00 moles of the above atom.

Please help giving brainliest out and be detailed and explain


Sagot :

N = n x No

No = avogadro's number = 6.02 x 10²³

n = N / No

n = 15 / 6.02 x 10²³

n = 2.49 x 10⁻²³ moles

the mass of one atom:

2.09 x 10⁻²¹ : 15 = 1.393 x 10⁻²² g

molar mass(MM) of the element:

MM = mass : mole

MM = 1.393 x 10⁻²² : 2.49 x 10⁻²³

MM = 5.594 = 6

the closest is Lithium

Mass for 5 moles:

mass = mole x molar mass

mass = 5 x 5.594

mass = 27.97 g