a meteorologist fills a weather observation balloon with hydrogen at a pressure of 1 atm at room temperature. if the volume of the balloon is 30 litres on the ground. what will it's pressure be at an altitude of 18km where the temperature is -50 degrees Celsius and pressure 0.1 atm?

The atomic radius of sodium is 186 pm and of chlorine is 100 pm. the ionic radius for na+ is 102 pm and for cl– is 181 pm. in going from na to cl in period 3, why does the atomic radius decrease while the ionic radius increases? a. the inner electrons in the sodium cation shield its valence electrons more effectively than the inner electrons in the chloride anion do. b. the inner electrons shield the valence electrons more effectively in the chlorine atom than in the chloride anion. c. the outermost electrons in chloride experience a smaller effective nuclear charge than those in the sodium cation do. d. the outermost electrons in chloride experience a larger effective nuclear charge than those in the sodium cation do. e. monatomic ions are bigger than the atoms from which they are formed.

How might this scientific phenomena be explained? a paper clip floats on water.

What happens to the temperature of a substance when the average kinetic energy of its particles increases?