Question

data analysis: atmospheric composition
use the images to complete the questions below.

1. which two elements are most common in the exosphere?

the 2 elements that are most common in the exosphere are hydrogen, and helium.

1. at which height are there equal amounts of free oxygen and helium?
2. you decide to measure the composition of atmospheric gases from a weather balloon. would the compositions be different than those found on the surface of the earth? explain.

Explanation:

Question 1

The exosphere is the outermost layer of the atmosphere. From atmospheric science knowledge, the exosphere is dominated by light elements. Hydrogen and helium are the most abundant due to their low molecular weight, allowing them to be present in the upper atmosphere.

Step 1: Identify the graph axes

The x - axis is height (km) and the y - axis is volume percentage. We need to find the height where the volume percentages of free Oxygen (O) and Helium (He) are equal.

Step 2: Locate the intersection of O and He curves

Looking at the graph, the curves for Oxygen (O) and Helium (He) intersect at a height. From the graph's x - axis (height) scale, the intersection occurs at approximately 500 km.

Atmospheric gas composition changes with altitude. Near the surface (troposphere), the atmosphere is well - mixed (homosphere) with a relatively constant composition (e.g., ~21% O₂, ~78% N₂, small amounts of others) up to about 80 - 100 km. A weather balloon typically operates within the troposphere or lower stratosphere. So, within the homosphere (where weather balloons usually fly), the composition of atmospheric gases (like the percentage of O₂, N₂, etc.) is similar to the surface. However, if the balloon were to go into the heterosphere (above ~80 - 100 km), composition would change, but weather balloons rarely reach there. So, for a typical weather balloon, the composition is not different from the surface because the lower atmosphere (troposphere, stratosphere up to ~80 km) is well - mixed.

Answer:

Hydrogen and Helium

Question 2