A can of coke contains 25 mL of carbon dioxide gas at 100kPa . If you take it on a hike up Mount Everest and the pressure decrease to 50 kPa , what will the new volume of the carbon dioxide gas in your coke can be ?

You exhale co2 which is produced during cellular respiration.  co2 combines with the water in your blood's plasma to make up one half of the body's most important buffer pair, carbonic acid.  the more physical activity you engage in, the more co2 your body is producing.  you can see this by putting some of the cabbage indicator in a glass and then blowing bubbles into it through a straw.  can you see a change in the color of the indicator?