Which ion has the same electron configuration as a mg2+ ion? a na+ b ca2+ c s2- d cl-

Compare and contrast physical changes with chemical changes.

At 300 mm hg, a gas has a volume of 380 l, what is the volume at standard pressure

Acalorimeter is to be calibrated: 51.203 g of water at 55.2 degree c is added to a calorimeter containing 49.783 g of water at 23.5c. after stirring and waiting for the system to equilibrate, the final temperature reached is 37.6 degree c. specific heat capacity of water (s = 4.18 j/g∙degree c). calculate the calorimeter constant. (smδt)warm water = -[(smδt)cold water + (calorimeterδtcold water)]