There is an average of 3.5 x 10^−2 kilograms of dissolved salt in each liter of seawater. the pacific ocean contains approximately 6.6 × 10^20 liters of seawater. about how many kilograms of dissolved salt are in the pacific ocean? enter your answer, in scientific notation, in the boxes. __×__10 kg

The answer is: 

   " 2.3 * 10^(19) "  kg  {dissolved salt in the Pacific Ocean} .

Explanation:

3.5 * 10⁻² * 6.6 * 10⁽²⁰⁾  = ? kg dissolved salt in the Pacific Ocean.

→ 3.5 * 10⁻² * 6.6 * 10⁽²⁰⁾  = 3.5 * 6.6 * 10⁻² * 10²⁰⁾ ;

Note the following property of exponents:

xᵃ * xᵇ = x⁽ᵃ⁺ᵇ⁾ ;  so;  10⁻² * 10²⁰ = 10⁽⁻² ⁺ ²⁰⁾ = 10⁽ ¹⁸ ⁾ ;

→ So; we can rewrite our expression as:

  3.5 * 6.6 * 10⁽ ¹⁸ ⁾ ;

→ Note: 3.5 * 6.6 = 23.1 ---> Round to 2 (two) significant figures:  23 ;

 23 * 10⁽ ¹⁸ ⁾ ;  to write in scientific notation; write the "whole number" as: "2.3" (a single digit, whole number integer, followed by a decimal", and adjust the exponent following the "10" accordingly, to make the value equal; and we have:
 
   " 2.3 * 10^(19) "  kg {dissolved salt in the Pacific Ocean} .

She should use 12/3 to measure