Answer:because some elements had not been discovered yet
Explanation:I juss took the Ed puzzle
It will be great if you searched on the internet then just questioning it on here because on here it takes a bit to get that so might as well google it
<span>Answer:
A 1.00 L solution containing 3.00x10^-4 M Cu(NO3)2 and 2.40x10^-3 M ethylenediamine (en).
contains
0.000300 moles of Cu(NO3)2 and 0.00240 moles of ethylenediamine
by the formula Cu(en)2^2+
0.000300 moles of Cu(NO3)2 reacts with twice as many moles of en = 0.000600 mol of en
so, 0.00240 moles of ethylenediamine - 0.000600 mol of en reacted = 0.00180 mol en remains
by the formula Cu(en)2^2+
0.000300 moles of Cu(NO3)2 reacts to form an equal 0.000300 moles of Cu(en)2^2+
Kf for Cu(en)2^2+ is 1x10^20.
so
1 Cu+2 & 2 en --> Cu(en)2^2+
Kf = [Cu(en)2^2+] / [Cu+2] [en]^2
1x10^20. = [0.000300] / [Cu+2] [0.00180 ]^2
[Cu+2] = [0.000300] / (1x10^20) (3.24 e-6)
Cu+2 = 9.26 e-19 Molar
since your Kf has only 1 sig fig, you might be expected to round that off to 9 X 10^-19 Molar Cu+2</span>
Molar mass neon = <span>20.1797 g/mol
20.1797 g ---------- 6.02x10</span>²³ atoms
? g ------------ 3.0 x 10²³ atoms
mass = 3.0 x 10²³ * <span>20.1797 / 6.02 x 10</span>²³
mass = 6.054x10²⁴ / 6.02 x 10²³
mass = 10.05 g
hope this helps!
Answer:
19-73 70-65-46 78-59-86 84-64
