Question

What is the mass in grams of 7.5 x 10^15 atoms of nickel?

Answer 1

Atomic mass Ni = 58.69 a.m.u

58.69 g ----------------- 6.02x10²³ atoms
?? g --------------------- 7.5x10¹⁵ atoms

58.69x (7.5x10¹⁵) / 6.02x10²³

=> 7.31x10⁻⁷ g

Answer 2

The mass of
`7,5.10^(15)` nickel atoms is
`7,34.10^(-7)g` grams

Step-by-step explanation:

We want to know how many grams
`7.5.10^(15)` nickel atoms equals and we know that one mole of any substance equals 6.021023 atoms

To know how many moles correspond
`7.5.10^(15)` nickel atoms apply a simple rule of three

`6,02.10^(23)  atoms\longrightarrow 1 mol\\7,5.10^(15) atoms\longrightarrow x\\x=((7,5.10^(15))(1mol) )/(6,02.10^23atoms) \\x= 1,25.10^(-8) mol`

The constant that relates the mass (grams) and the amount of substance (mol) is the molecular mass of the element The nickel molar mass is 58.69g/mol

to know how many grams of nickel correspond
`1,25.10^(-8) mol` mol we apply a rule of three simple

`1 mol \longrightarrow 58.69 g\\1,25.10^(-8)\longrightarrow x \\x= ((1,25.10^(-8)mol)(58.69g) )/(1mol) \\x=7,34.10^(-7)g`

The mass of
`7,5.10^(15)` nickel atoms is
`7,34.10^(-7)g` grams