2.55 gram of an alloy of silver and zinc on treatment with excess dilute hydrochloric acid gave 170 CC Of hydrogen gas of STD. If silver remained unsolved calculate the percentage Composition of the alloy .
( Alamic masses of Zn: 65, H:1)

Solid tin exists in two forms: white and gray. for the transformation sn(s, white) → sn(s, gray) the enthalpy change is -2.1 kj/mol and the entropy change is -7.4 j/(mol*k). a. calculate the gibbs free energy change for the conversion of 1.00 mol white tin to gray tin at -30℃. b. will white tin convert spontaneously to gray tin at -30℃? c. at what temperature are white and gray tin thermodynamically equivalent at a pressure of 1 atm?