How many half-lives will it take for the concentration of the n2o to reach 30 % of its original concentration?

Number of lives required to reach 30% of the its original concentration is 2.

Explanation:

Number of half lives are calculated by using formula :

       ............(1)

where,

a = amount of reactant left after n-half lives

= Initial amount of the reactant

n = number of half lives

Here we have:

Initial concentration of nitrogen dioxide =

Concentration of nitrogen dioxide after n number of half lives = a

a = 30% of x :

n = 1.736 ≈ 2

Number of lives required to reach 30% of the its original concentration is 2.

in scientific notation, the value of the  speed of light in a vacuum

  will be written as 2.995 * 10^8. when this value is represented in the form of

  a * 10^b, then, a = 2.995 and b = 8.

the value of the speed of light in a vacuum given above can also be rounded up to approximately 300000000. in this case, the scientific notation will be written as 3 *10^8.