The half-life of a positron is very short. it reacts with an electron, and the masses of both are converted to two gamma-ray photons. e+10 +0−1e⟶ this reaction is called an annihilation reaction. the mass of an electron or positron is 9.109×10−31 kg. (a) calculate the energy produced by the reaction between one electron and one positron. (b) assuming that the two γ-ray photons have the same frequency, calculate this frequency. j = hz

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

Match the mixture with the substance// i really need on this guys (it’s a pic btw)

Word equation for k(s)+h2o(l) yield koh(aq) + h2(g)