What produces hydrogen ions as the only positive ions in aqueous solution?
1) koh 3)nh3
2) hbr 4)nacl

Ageologist determines that a sample of a mineral can't be scratched by a steel nail but can be scratched by a masonry drill bit. based on this information, the sample mineral has to be softer than a. orthoclase. b. fluorite. c. apatite. d. corundum.

Answer asap : ( a. how does mucus prevent the entry of pathogens? b. describe two ways white blood cells protect us from pathogens.

Convert the temperature of dry ice, –77 ∞c, into degrees fahrenheit and kelvin.