The boiling point of a pure substance is defined as the temperature at which:
a) the kinetic energy of the molecules begins to increase
b) the vapor pressure equals the external pressure
c) the molecules of the substance break apart
d) the liquid phase can be completely evaporated
in advance

Nconcentration refers to the molar concentration of an ion in solution. it may be identical to, or greater or less than, the molar concentration of the compound containing the ion that was used to make the solution. for soluble salts, the molarity of a particular ion is equal to the molarity of that compound times the subscript for that ion. for example, 1 m of alcl3 is 1 m in al3+ and 3 m in cl−. 1 m of (nh4)2so4 is 2 m in nh4+ and 1 m in so42−. part a what is the concentration of k+ in 0.15 m of k2s? view available hint(s) nothing m m part b if cacl2 is dissolved in water, what can be said about the concentration of the ca2+ ion? view available hint(s) if is dissolved in water, what can be said about the concentration of the ion? it has the same concentration as the cl− ion. its concentration is half that of the cl− ion. its concentration is twice that of the cl− ion. its concentration is one-third that of the cl− ion. part c a scientist wants to make a solution of tribasic sodium phosphate, na3po4, for a laboratory experiment. how many grams of na3po4 will be needed to produce 550 ml of a solution that has a concentration of na+ ions of 0.700 m ? express your answer numerically in grams. view available hint(s) mass of na3po4 n a 3 p o 4 = nothing g provide feedback

Scientists are often interested in knowing the molar heat of combustion – the heat released during the combustion of one mole of a substance. use the periodic table to find molar masses. how many moles of ethanol are present in the sample?

Describe the basic structure of the atom