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If a tree dies and the trunk remains undisturbed for 13,535 years, what percentage of original 14C/12C ratio is still present? (t1/2= 5730 years)

For a particular chemical reaction ΔH = 5.8 kJ and ΔS = –23 J/K. Under what temperature condition is the reaction spontaneous?

The reduction potentials for Au 3+ and Ni 2+ are as follows:           Au 3+ + 3e – → Au     E° = +1.50 V           Ni 2+ + 2e – → Ni     E° = –0.23 V Calculate ΔG° (at 25°C) for the reaction           2Au 3+ + 3Ni → 3Ni 2+ + 2Au

A 5.95-g sample of AgNO3 is reacted with BaCl2 according to the equation         2AgNO3(aq)+ BaCl2(aq) —> Ba(NO3)2(aq) + 2AgCl(s)to give 4.07 g of AgCl. What is the percent yield of AgCl?

Which type of impression tray is pictured below?  

The use of CEREC (CAD/CAM) restorative systems benefit the patient in which of the following ways?

14 karat gold contains ______% gold.

An impression is a positive reproduction of teeth and surrounding oral tissues.

What can be used to  polish gold extraorally? 

What is the working time of regulalr-set alginate impression material?