The average atomic mass of Rb-85 (84.912 amu) and Rb-87 (86.909 amu) is 85.47 amu. Calculate the percentage abundance of each isotope.

It is 4.92 e-4 sorry if i am wrong

According to arrhenius theory of acid and bases, an acid is a proton donor, while base donates hydroxyl ions. further, acid and base reacts to form salt and water.consider following example.hcl    +      h2o          →      cl-          +      h3o+here, hcl has donated a proton, hence it is an acid.now consider following reactionhcl      +      naoh            ↔      nacl      +        h2oin this reaction, hcl donates proton, hence it is acid. on other hand, naoh donates hydroxyl ion (i.e. hence it is a base.   

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The best answer is the third option, a pottery art studio.