Strips of aluminum and lead will react with hydrochloric acid, but a silver strip will not. A reaction was observed when an Al strip was placed in solution of Pb(NO3)2 and AgNO3. No reaction was
observed when an Ag strip was placed in a Pb(NO3)2 solution. Arrange the metals and hydrogen in
a relative reactive series, listing the most reactive first.

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.

a:

by the combination of an unlimited number of elements

it is the most commonly accepted one