Question

1) 4.25 x 1022 atoms Ni = _g Ni

Answer 1

Mass of Ni = 4.14 grams

Step-by-step explanation:

Molar mass : It is the amount of substance present in 1 mole of the molecules.

Moles : It is the quantity that contains as many atoms as present in 12 gram of C-12. This is equal to Avogadro Number .

`Avogadro\ Number= N_(0)`

`N_(0)=6.022* 10^(23)`

Molar mass of Ni = 58.69 g/mole

Moles can be calculated by two formula:

`moles(n)= (given\ mass(m))/(Molar\ mass(M))`

`n=(m)/(M)`........(1)

And ,

`moles=(Number\ of\ atoms(N))/(N_(0))`

`n=(N)/(N_(0))`.........(2)

Comparing equation 1 and 2

`(m)/(M)=(N)/(N_(0))`

`N = 4.25* 10^(22)`

`N_(0)=6.022* 10^(23)`

M = 58.69 g/mole

Put these value in the formula and solve for m

`(m)/(58.69)=`

`(4.25* 10^(22))/(6.022* 10^(23))`

`(m)/(58.69) = 0.0705`

`m=58.69* 0.0705`

m = 4.14 gram

Mass of Ni = 4.14 grams

Second Approach :

Find the moles first using :

`n=(N)/(N_(0))`

Then put value of n in the formula(1) and solve for m

`n=(m)/(M)`........(1)