The standard enthalpy of formation of Ca2+ (g) (∆H = 1934 kJ/mol) The first ionization of Ca H=590 kJ/mol
The second ionization of Ca H=1151 kJ/mol
I need to write an equation for the process of the standard enthalpy of formation of Ca2+. Can you help and explain please?

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.

Which diagram represents the phase tha occurs after a solid melts?

Magnesium is the limiting reactant in this experiment. calculate the theoretical yield of mgo for each trial. trial 1: trial 2: data mass of empty crucible with lid trial 1: 26.688 trial 2: 26.681 mass of mg metal, crucible, and lid trial 1: 26.994 trial: 2 26.985 mass of mgo, crucible, and lid trial 1: 27.188 trial 2: 27.180