53. A piece of zinc reacts completely with hydrochloric acid, HCl(aq), to produce an aqueous solution of
zinc chloride, ZnCl2(aq), and hydrogen gas.
a. Use the data shown below to determine the
enthalpy of reaction per mole of zinc.
AH; of HCl(aq) = -167.2 kJ/mol
AH; of ZnCl2(aq) = -488.2 kJ/mol
Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g)
b. What mass of zinc must be used for 123 kJ of heat
to be given off?
=-
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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

Displacement is the slope of a velocity vs. time graph a. true b. false

Which sentence from holes contains an implied personality trait? stanley and his parents had tried to pretend that he was just going away to camp for a while, just like rich kids do. he'd just been in the wrong place at the wrong time. stanley felt somewhat dazed as the guard unlocked his handcuffs and led him off the bus. stanley nodded to show he understood