4. What is the mass in grams of 100 atoms of carbon-12?

Mass = 199.2 g

Explanation:

Given data:

Mass in gram = ?

Number of atoms of C-12 = 100 atom

Solution:

First of all we will calculate the number of moles of C-12 in 100 atoms by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

6.022 × 10²³ is called Avogadro number.

1 mole = 6.022 × 10²³ atoms

100 atoms×1 mol / 6.022 × 10²³ atoms

16.6× 10²³ moles

Mass of C-12:

Mass = number of moles × molar mass

Mass = 16.6 × 10²³ mol × 12 g/mol

Mass = 199.2 g

your answer would be a. 12.5 kg