How many total number of all the elements present in mole of (NH4)2 Cr2O7? Thanks a lot.

1 Answer
anor277
Nov 19, 2016

We use #"Avogadro's number, "N_A=6.022xx10^23*mol^-1#, to quantify the numbers of individual atoms in a mole, i.e. a #"252.07 g"# mass of #(NH_4)_2Cr_2O_7#.......

Explanation:

In such a mass, there are #2xxN_A# #"nitrogen atoms"#, and

#8xxN_A# #"hydrogen atoms"#, and

#2xxN_A# #"chromium atoms"#, and

#7xxN_A# #"oxygen atoms"#.

Here we use #N_A# as a counting number, i.e. as we would use the number #10#, or a #"million"#, or a #"dozen"#.

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