Select the correct answer.

Avogadro's number is a constant that helps scientists count atoms and molecules. It is approximately equal to [tex][tex]$602,200,000,000,000,000,000,000$[/tex][/tex]. How is this number expressed in scientific notation?

A. [tex][tex]$\frac{6.02}{10^{22}}$[/tex][/tex]
B. [tex][tex]$\frac{1}{6.02 \times 10^2}$[/tex][/tex]
C. [tex][tex]$6.02 / 10^{23}$[/tex][/tex]
D. [tex][tex]$6.02 \times 10^{23}$[/tex][/tex]
E. [tex][tex]$6.02 \times 10^{-23}$[/tex][/tex]



Answer :

To solve the problem of expressing Avogadro's number [tex]\( 602,200,000,000,000,000,000,000 \)[/tex] in scientific notation, follow these steps:

1. Identify the significant figures: In the given number, the significant figures are [tex]\( 6022 \)[/tex], noting that the trailing zeros are also significant in a scientific context for this representation.

2. Convert to scientific notation:
- We need to express the number in the form [tex]\( a \times 10^b \)[/tex], where [tex]\( 1 \leq a < 10 \)[/tex] and [tex]\( b \)[/tex] is an integer.
- For the number [tex]\( 602,200,000,000,000,000,000,000 \)[/tex], we move the decimal point 23 places to the left to get a number between 1 and 10.

So, [tex]\( 602,200,000,000,000,000,000,000 \)[/tex] becomes [tex]\( 6.022 \times 10^{23} \)[/tex].

3. Round appropriately:
- Often, constants such as Avogadro’s number are rounded to three significant figures for simplicity. Therefore, [tex]\( 6.022 \times 10^{23} \)[/tex] is approximated as [tex]\( 6.02 \times 10^{23} \)[/tex].

Given the calculation, the correct scientific notation for Avogadro's number is [tex]\( 6.02 \times 10^{23} \)[/tex].

Thus, the correct answer is:
D. [tex]\( 6.02 \times 10^{23} \)[/tex]