19-20. KO2 is used in a closed-system breathing apparatus. It removes carbon dioxide and water from exhaled air. The reaction for the removal of water is: KO2 + H2O O2 + KOH. The KOH produced is used to remove carbon dioxide by the following reaction: KOH + CO2 KHCO3.

a. What mass of KO2 produces 5000 g of O2?

b. What mass of CO2 can be removed by 1000 g of KO2?

Which is true of chemicals? a. things containing chemicals always cost a lot of money. b. chemicals are never dangerous. c. chemicals are in many substances in a home. d. chemicals are rarely found on earth.

Astudent is trying to create a table that compares hypotheses, theories, and laws. hypothesis theory law do scientific researchers formulate it? yes yes yes does it explain why things happen? yes yes no yes yes yes is it used to make predictions? no yes yes which of the following questions would most likely fill the blank in the table? is it an intelligent guess? is it newly formulated? is it based on observations? has it been proved?

Choose all the answers that apply. fluorine (f) has an atomic number of 9 and an atomic weight of 18.99. fluorine has a. 9 protons b. 10 neutrons c. 18 electrons d. an atomic mass of 19 e. at least one isotope