Answer:
Explanation:
THE CORECT QUESTION
A 50.0 mL solution of 0.127 M KOH is titrated with 0.254 M HCl. Calculate the pH of the solution after the addition of each of the given amounts of HCl.
SOLUTION
Get the concentration of the HCl first using titration formula
CA X V A / CB VB = NA/ NB
Equation of reation; KOH + HCl => KCl + H2O
CA = 0.254 M
CB = 0.127
VA = 1/0.254 = 3.937
CA (after the addition) = 0.127 x 50 / 3.937
= 1.612 M
But pH = - Log[hydrogen ion]
= -log 1.612
=
2,8,1
It's in group 1, so its outershell only has 1 electron, and the other shells are completely filled, so 2 then 8. :)
<span>If you give it a good search, the most used answer would probably be as follows,
</span><span>In 1914 Henry Moseley found a relationship between an element's X-ray wavelength and its atomic number (Z), and therefore rearranged the table by nuclear charge / atomic number rather than atomic weight. Before this discovery, atomic numbers were just sequential numbers based on an element's atomic weight. Moseley's discovery showed that atomic numbers had an experimentally measurable basis.
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Hope this helps!
Answer:
THE EMPIRICAL FORMULA FOR THE UNKNOWN COMPOUND IS C7H9O
Explanation:
The empirical formula for the unknown compound can be obtained by following the processes below:
1 . Write out the percentage composition of the individual elements in the compound
C = 75.68 %
H = 8.80 %
O = 15.52 %
2. Divide the percentage composition by the atomic masses of the elements
C = 75 .68 / 12 = 6.3066
H = 8.80 / 1 = 8.8000
O = 15.52 / 16 = 0.9700
3. Divide the individual results by the lowest values
C = 6.3066 / 0.9700 = 6.5016
H = 8.8000 / 0.9700 = 9.0722
O = 0.9700 / 0.9700 = 1
4. Round up the values to the whole number
C = 7
H = 9
O = 1
5 Write out the empirical formula for the compound
C7H90
In conclusion, the empirical formula for the unknown compound is therefore C7H9O
Since there is 9.47 x 1021 atoms of copper in 1 gram, and 8.96 grams/cc is the density of copper, then 9.47 x 8.96 =84.85 x 1021 atoms of copper in the one cubic centimeter of copper.
