Question

Explain how you know it must be oxygen. Where did the oxygen come from?

Answer 1

Hello, I didn’t super understand your question. But I’ll try my best to answer it for you. :)


At least half of Earth's oxygen comes from the ocean. Scientists estimate that 50-80% of the oxygen production on Earth comes from the ocean. The majority of this production is from oceanic plankton — drifting plants, algae, and some bacteria that can photosynthesize.

Like trees and other plants, phytoplankton can absorb sunlight and turn it into energy through a process called photosynthesis. Fortunately for us, photosynthesis also creates oxygen as a waste product, which the phytoplankton and plants expel — just like how humans and other animals produce carbon dioxide when we exhale.

Answer 2

Answer:

Copper oxide is the only product, and it contains copper and oxygen.

One of the reactants is copper, so the other reactant must be oxygen.

The copper metal must have combined with something in the air.

Explanation: