The air we breathe is mainly a mixture of nitrogen gas, oxygen gas, and carbon dioxide. What would be the total pressure when the partial pressure of oxygen gas is 0.21 atm, the partial pressure of carbon
dioxide gas is 0.01 atm, and the partial pressure of nitrogen gas is 0.78 atm.

Ionic compounds are made of ions, and yet the overall charge of an ionic compound is neutral. why?

City a and city b had two different temperatures on a particular day. on that day, four times the temperature of city a was 8â° c more than 3 times the temperature of city b. the temperature of city a minus twice the temperature of city b was â’3â° c. what was the temperature of city a and city b on that day? city a was 5â° c, and city b was 4â° c. city a was 3â° c, and city b was â’1â° c. city a was 8â° c, and city b was â’3â° c. city a was 5â° c, and city b was â’5â° c.

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.