Question

Planet Earth has a mass of 5.9726 × 10 24 kilograms. And although 70% of the Earth's surface is made of water, the water's mass is only 5 × 10 -4 percent of the Earth's total mass. Use scientific notation to estimate the mass of the planet's water. In your final answer, include all of your estimates and calculations.

Answer 1

Given parameters:

Mass of the earth = 5.9726 x 10²⁴kg

Mass of percent water on earth = 5 x 10⁻⁴% of the total mass of the earth

Unknown:

Mass of water on earth = ?

Solution

This is pretty straight forward;

Mass of water on earth = mass percent of water x mass of earth

Input the parameters and solve;

Mass of water on earth =
`(5 x 10^(-4) )/(100)` x 5.9726 x 10²⁴

= 5 x 10⁻⁴ x 10⁻² x 5.9726 x 10²⁴

= 5 x 5.9726 x 10⁻⁴⁺⁽⁻²⁾ ⁺²⁴

= 29.863 x 10¹⁸kg

or 2.9863 x 10¹⁹kg

Mass of water on earth is 2.9863 x 10¹⁹kg