He gas is contained in a one-liter flask that is connected to an empty one-liter flask with a closed stopcock between the two flasks. when the stopcock is opened some of the he enters the evacuated flask. for this system
a. ? h is positive and ? s is negative
b. ? h is zero and ? s is positive
c. ? h is zero and ? s is negative
d. ? h is negative and ? s is positive

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.

Water's surface tension and heat storage capacity are accounted for by its a) orbitals b) weight c) hydrogen bonds d) mass e) size

What is the molarity of the solution produced when 145 g of nacl is dissolved in sufficient water to prepare 2.75 l of solution?