Hey there!
mass of sample = 2.51 g of Aspirin
Number of moles of base ( NaOH ) :
M*V = 27.36*0.5106 = 13.9700 mmol of base
M*V = 13.68*0.516 = 7.05888 mmol of acid
pKa calculation:
pH = pKa + log(A-/HA)
3.48 = pKa + log(7.05888 / (13.9700 -7.05888))
Pka =3.49 - log(7.05888 / (13.9700 -7.05888))
pKa = 3.48
Molar mass calculation:
molar mass = mass/mol
(2.51)/(13.9700 *10⁻³) =
molar mass 180 g/mol approx
Hope that helps!
The trend of atomic radius in the periodic table is increasing from right to left and from top to bottom. In reference to the table, oxygen has smaller radius compared to carbon, which is smaller than aluminum and which is also smaller than potassium. Thus, the trend from smallest to biggest is oxygen carbon, aluminum and potassium.
The statement that best describes the trend in first ionization enery of elements on the periodic table is:
<span>It generally decreases down a group because valence electrons are farther from the nucleus.
The first ionization energy measures how difficult is to release an electron from the outermost shell. The higher the ionization energy the more difficult it is to release an electron, the lower the ionication energy the easier to release an electron.
As the atomic number of the atom increases (which is what happens when you go down a group) the furthest the outermost shell of electrons will be (the size of the atoms increases) and so those electrons require less energy to be released, which means that the ionization energy decreases.
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The answer would be 3.37x10 to exponent 17.
