4/9+3/9=what is the answer to this problem

What is the ph of a solution that has a hydrogen ion concentration of 1.0 * 10 -9 m?

How does the presence of oxygen affect the chemical pathways used to extract energy from glucose?

Asample of freon gas has a volume of 2.23 liters, a pressure of 4.85 kpa, and a temperature of -1.36°c. calculate the volume at a pressure of 1.38 kpa and a temperature of 5.5°c. (show work)