Answer:
<span>The mole concept is important in chemistry because, "</span>Atoms and molecules are very small and the mole concept allows us to count atoms and molecules by weighing macroscopic amounts of material".
Explanation:
To understand this question lets take an example of Hydrogen atom. Let suppose you need to react Hydrogen with Oxygen. You need exactly Two Hydrogen atoms and one Oxygen atom to form one water molecule.
The mass of 1 hydrogen atom is 1.76 × 10⁻²⁴ grams. How will you count the Hydrogen atoms??? How can you measure exactly for 1 Million Hydrogen Atoms???
Answer to these questions and Calculations lies in Mole. It is found that 1 Mole of Hydrogen weights exactly 1.008 gram and contains 6.022 × 10²³ atoms. Now, having this reference in hand you can calculate for any number of Hydrogen atoms.
Result:
So the Mole helps us to zoom a microscopic level to a macroscopic level. :)
A covalent compound is made when two or more nonmetal atoms bond by sharing valence electrons. The shared valence electrons between two nonmetal atoms is called a covalent bond. Covalent bonds are formed when two atoms begin sharing electrons.
Answer: The density of lead will be 
Explanation:
Density is defined as the mass contained per unit volume.
Given : Mass of lead=
Volume of lead =
Putting in the values we get:
Thus density of lead will be
Number of atom in one mole = 6.022 × 10²³
So, in 3.5 moles, it would be: = 6.022 × 10²³ * 3.5 = 2.1 × 10²⁴
In short, Your Answer would be 2.1 × 10²⁴ atoms
Hope this helps!
