HW 2-11 Adding and Subtracting with Scientific Notation Add or subtract with your numbers in scientific notation. 1) One hydrogen atom is approximately 1.7 x 10-27kg. One oxygen atom is approximately 2.7 x 10-26kg. Two hydrogen atoms with one oxygen atom makes one atom of water. Find the mass of one atom of water.

2) The approximate total surface area of the Earth is 5.1 x 108 km2. Salt water has an approximate surface area of 352,000,000 km2 and freshwater has an approximate surface area of 9 x 106 km2. A) How much of the Earth’s surface is covered by water, including both salt and freshwater? Write your answer in scientific notation.

B) How much of the Earth’s surface is covered by land? Write your answer in scientific notation.

3) The sun is approximately 230,000,000,000 meters from Mars. The sun is approximately 1.5 x 1011meters from Earth. What is the approximate distance from Earth to Mars?

4) On average, Mercury is about 57,000,000 km from the sun, whereas Neptune is about 4.5 x 109 km from the sun. What is the difference between Mercury’s and Neptune’s distances from the sun?

5) Find the combined mass of Earth and Venus. Earth is approximately 5.9 x 1024kg and Venus is approximately 4.9 x 1024kg.