Question

What is the mass of 1.204 x 1022 atoms of lead? (Atomic mass of Pb= 207)​

Answer 1

Given :

• Number of atoms of lead = 1.204 × 10²²
• Atomic mass of lead = 207

To find :

Mass of given number of atoms

Formula used :

• Number of atoms = Number of mole × Avogadro's Number
• Number of mole = mass ÷ atomic mass

Solution :

First of all we will find number of mole of lead present in given number of atoms

$\sf \implies \: Number \: of \: atoms \: \: of \: lead \: = \: Number \: of \: moles \: of \: lead \times \: Avogadro's \: Number \\ \\ \sf \implies \: Number \: of \: moles \: of \: lead \: = \: \dfrac{ Number \: of \: atoms \: \: of \: lead \:}{ Avogadro's \: Number} \\ \\ \sf \implies \: Number \: of \: moles \: of \: lead \: = \dfrac{1.204 \times {10}^{22} }{6.02 \times {10}^{23} } \\ \\ \sf \implies \: Number \: of \: moles \: of \: lead \: = \: \dfrac{0.2}{10} \\ \\ \sf \implies \: Number \: of \: moles \: of \: lead \: = 0.02$

Now ,

Number of mole of lead = Mass ÷ Atomic mass

Mass = Number of moles of lead × Atomic mass

Mass = 0.02 × 207

Mass = 4.14 grams

ANSWER : 4.14 grams

Answer 2

Answer:

4.14 grams

Explanation:

Number of atoms of lead = 1.204×$10^{22}$

Atomic Mass of Lead = 207 u (207 gm)

=> Number of atoms of lead = Number of moles of lead×Avagadro's Number

=> Number of moles of lead = 0.02

Now,

0.02×207

= 4.14 = ANSWER